bridget physics
which of the following has the largest momentum relative to earths surface
a pickup truck speeding along the highway
which of these has it's center of mass where no mass exists
basketball
if Burl carried Paul piggy-back while standing in the middle of a scaffold, the tensions in the two supporting ropes would
be equal
why did Newton think there was a force acting on the moon
because the moon acts in a curved path
You can swing your legs to and fro more frequently when your legs are
bent
a very massive object A and a less massive object B move toward each other under the influence of gravity which froce if either is greater
both forces are the same
a ball rolls off the edge of a table at the same time another ball drops vertically from the same table. the ball to hit the floor first is the
both hit at the same time
mechanical energy can be in the form of
both kinetic and potential energy
the law of inertia applies to
both moving and nonmoving objects
which requires more work: lifting a 70-kg sack vertically 2 meters or lifting a 35-kg sack vertically 4 meters?
both require the same amount of work
which produces more force: driving into a very massive concrete wall with no "give", or having a head on collision with an identical car moving towards you at the same speed
both the same
the center of mass of a human body is located at a point that
changes as a person bends over
according to kepler, the speed of a planet is fastest when it is ________ to the sun
closest
the direction of a gravitational field is
opposite to the gravitational attraction
the force due to gravity that acts on a block of ice that slides down an icy ramp
remains equal to mg at all angles
If a stone falls to the bottom of a mineshaft in 6 seconds, then the depth of the shaft is about
180 m
a player catches a ball consider the action force to be the impact of the ball against the players glove what is the reaction to this force
the force the glove exerts on the ball
according to newton the greater the mass of interacting objects
the greater the gravitational force between them
the winner in a tug of war exerts the greatest force on
the ground
Compared to the mass of an apple on Earth, the mass of the apple on the Moon is
the same
a ball is thrown upwards and returns to the same location compared with its initial speed. Its speed when it returns is about
the same
dr. chuck projects a ball horizontally from a lab bench. If the projection speed of the ball were greater, the time in the air would be
the same
if the sun collapsed to a black hole, Earth's gravitational attraction to it would be
the same
A tiny gun made of a strong but very light material fires a bullet more massive than the gun itself. For such a weapon
the target would be safer than the shooter
when a boxer is moving away from a punch, the force experienced is reduced because
the time of contact is increased
a ball rolling down an incline has its maximum potential energy at
the top
the unit for power is
watt
a vehicle undergoes acceleration when it
- gains speed - loses speed - changes it direction
Suppose you try loosening a nut with a wrench, and the nut doesn't give at all. You increase your chance of success if you
- have a friend help you pull the wrench -be sure to exert force perpendicular to the lever arm -exert a larger force -extend the lever arm
The acceleration produced by a net force on an object is
- inversely proportional to the mass of the object -directly proportional to the magnitude of the net force - in the same direction as the net force
the gravitational force between two massive spheres
- is always an attraction -depends on how massive they are -depends inversely on the square of the distances between them
The earliest and most influential Greek philosopher was Aristotle, who among many contributions taught that
- the four elements are earth, water, air and fire - all motion is either natural or violent - violent motion requires a sustained push or pull
If the sun were twice as massive
-It's pull on Earth would double. -the pull of Earth on the Sun would double.
when an ice skater pulls in his hands to turn faster
-angular momentum must be conserved -his moment of inertia changes -his rotational speed changes
when air drag affects the motion of projectiles, they don't travel
-as high -as far
it takes Neptune a longer time to orbit the Sun than Earth does because Neptune
-has much further to go -goes much slower -both of these
You experience weightlessness
-in the absence of a supporting surface. - in a freely falling elevator. - momentarily when you step off a chair.
In order to increase the final momentum of a golf ball, we could
-increase the force acting on it - follow through when hitting the ball - increase the time of contact with the ball -swing as hard as possible
An object in mechanical equilibrium is an object
-moving with constant velocity -having no cahnges in velocity -at rest
which of these vary for satellites in elliptical orbits
-speed -momentum -kinetic energy
when representing velocity as a vector
-the direction of the arrow shows the direction of motion -the length of the arrow represents the speed -the length of the arrow is drawn to a suitable scale
A karate expert executes a swift blow and breaks a cement block with her bare hand.
-the forces on both the block and the experts hand have the same magnitude -the times of impact on both the block and the experts hand are the same - the impulses on both the block and the experts hand have the same magnitude
the force of an apple hitting the ground depends upon
-the speed of the apple just before it hits -the time of impact with the ground -whether or not the apple bounces -air resistance on the apple as it falls
a collision is considered elastic if
-there is no lasting deformation -the objects don't stick together - the objects that collide don't get warmer -after the collision, the objects have the same shape as before the collision.
a book weighs 4 N when held at rest in your hands the net force on the book is
0 N
If a weight scale shows that you weigh 200 kg on the surface of the Earth, and then you skydive with both of your feet attached to the scale, you will read a weight of
0 kg
suppose the gravitational force between two spheres is 30 N. If the magnitude of each mass doubles, what is the force between the masses
120 N
the power expended doing 100 J of work in 50 s is
2 W
a 2-kg box of taffy candy has 40 J of potential energy relative to the ground. Its height above the ground is
2 m
the circumference of a bicycle wheel is 2 meters. If it rotates at 1 revolution per second then its linear speed is
2 m/s
The total time it takes a projectile fired straight up at 10 m/s to reach the top of its path and return to its starting point is about
2 secs
a ball player wishes to determine pitching speed by throwing a ball horizontally from an elevation of 5 m above the ground level. the ball lands 20 m downrange. the players pitching speed is about
20 m/s
a car has a mass of 1000 Kg and accelerates at 2 m/s^2 what net force is accelerated on the car
2000 N
a hydraulic jack is used to lift objects such as automobiles. If the input force is 200 N over a distance of 1 meter, the output force over a distance of 0.1 meter is ideally
2000 N
a car traveling at 22 m/s comes to an abrupt halt in 0.1 seconds when it hits a tree what is the deacceleration of the car
220 m/s^2
Suppose the gravitational force between two massive spheres is 100 N. If the distance between the spheres is doubled, what is the force between the masses
25 N
When a woman stands with two feet on a scale, the scale reads 280 N. When she lifts one foot, the scale reads
280 N
suppose the gravitational force between two spheres is 70 N. If the distance between the spheres is halved, what is the force between the masses?
280 N
the speed of a 4kg ball with a momentum of 12 kg m/s is
3 m/s
a roller coaster ride with 6 passengers takes 3 minutes neglecting friction a similar ride with 12 passengers aboard would take
3 minutes
a motorcycle of mass 100 kgs slowly rolls off the edge of a cliff and falls for three seconds before reaching the bottom of a gully. its momentum upon hitting the ground is
3,000 kg m/s
Nellie pulls on a 10-kg wagon with a constant horizontal force of 30 N. If there are no other horizontal forces, what is the wagon's acceleration?
3.0 m/s^2
a 2000 kg car experiences a braking force of 10,000 N and skids to a stop in 6 seconds the speed of the car just before the brakes were applied was
30 m/s
a pot that falls from a ledge and hits a ledge and hits the ground 45 m below hits the ground at
30 m/s
a 500-N parachutist opens his parachute and experience an air resistance force of 800 N. the net force on the parachutist is then
300 N upward
when a karate chop breaks a board with a 3000-N blow, the amount of force that acts on the hand is
3000 N
a 300 kg bear grasping a vertical tree slides down at a constant velocity the friction force between the tree and the bear is
3000 N F=MA
Suppose you take a trip that covers 180 km and takes 3 hours to make. Your average speed is
60 km/h
a freely falling object starts from rest after falling for 6 seconds it will have a speed of about
60 m/s
how much power is expended if you lift a 60 N crate 10 meters in 1 second?
600 W
as you crawl toward the edge of a large freely-rotating horizontal turntable in a carnival funhouse, the angular momentum of you and the turntable.
remains the same but the revolutions per minute decrease
while a rock thrown upward at 50 degrees to the horizontal rises, neglecting air drag, its horizontal component of velocity
remains unchanged
two people are balanced on a seesaw. If one person leans inward toward the center of the seesaw, that person's end of the seesaw tends to
rise
a projectile that is fired vertically from the surface of earth at 5 km/s will
rise and fall back to earths surface
a projectile that is fired vertically from the surface of earth at 8 km/s will
rise and fall back to earths surface
The force exerted on the tires of a car to directly accelerate it along a road is exerted by the
road
when railroad tracks make a curve, the outer track is longer. this means a wheel that rides on the outer track needs to somehow
roll faster than the wheel on the inner track
a pair of toys freight cars one twice the mass of the other, fly apart when a compressed spring that joins them is released. the spring exerts the greater force on the
same each
a projectile that falls freely around the earth is called a
satellite
the chef at the infamous Fattening Tower of Pizza tosses a spinning disk of uncooked pizza dough in the air. The disk's diameter increases during flight, while its rotational speed
slows
a table tennis ball launcher is fired. compared to the impulse on the ball, the impulse on the launcher is
smaller
a meteor that originally was heading south breaks up into 2 chunks. one of the chunks moves southwest. the second chunk was not immediately found, but scientists guessed that they should look for an object heading
southeast
two factors that greatly affect air resistance on falling objects are frontal area and.....
speed
which of the following is not a vector quantity
speed
If you drop a stone into a hole drilled all the way to the other side of Earth (neglect the molton core) the stone will
speed up until it reaches earths other side
a moving object has
speed, velocity, momentum, energy
tension is actually a force that tends to
stretch something
a ball thrown upwards and caught when it comes back down in the absence of air resistance the speed of the ball when caught would be
the same as the speed it had when thrown upwards
A car traveling at 100 km/hr strikes an unfortunate bug and splatters it. The force of impact is
the same for both
An automobile and a golf cart traveling at the same speed collide head-on. The impact force is
the same for both
the orbital path of a satellite has two focal points. when both focal points are together
the satellite path is a circle
two students engaged in a tug-of-war each pull a rope in opposite directions with a force of 400 N. the net force on the rope is..
zero and rope tension is 400 N
which of the following would NOT be considered a projectile
a cannonball rolling down a slope
which has greater kinetic energy
a car of half the mass traveling at 60 km/hr
It is correct to say that impulse is equal to
a corresponding change in momentum
A machine that promises more energy output than input is
a fantasy
a dropped ball gains speed because
a gravitational force acts on it
Suppose an object is in free fall. Each second the object falls
a larger distance than in the second before
a sandbag motionless in outer space is hit by a three-times-as massive sandbag moving at 12 m/s. They stick together and move at a speed of
a. 3 m/s b. 4 m/s c. 6m/s d. 8 m/s e. none of the above answer: E
While a car travels around a circular track at a constant speed, its
a. acceleration is zero b. velocity is zero c. inertia is zero d. none of the above answer: D
Nellie Newton holds an apple in her hand. If the action is Earth pulling on the apple, then the reaction is
a. her hand providing a normal force on the apple b. her hand pushing y on the apple c. neither a and b answer is C
when a pair of 10 N forces act on a box of candy the net force on the box is
a.. zero b.about 14 N c. 20 N D. any of the above depending on the direction of the forces Answer: D
when you jump from an elevated position you usually bend your knees upon reaching the ground, which makes the time of the contact about 10 times that of a stiff-legged landing. In this way the average force your body experiences is
about 1/10 as great
a package falls off a truck that is moving at 30 m/s. neglecting air resistance the horizontal speed on the package just before it hits the ground is
about 30 m/s
the famous leaning tower of pisa does not topple over because its center of gravity is
above a place of support
If more horizontal force is applied to a sliding object than is needed to maintain a constant velocity
accelerates in the direction of the applied force
If an apple experiences a constant net force, it will have a constant
acceleration
a freely falling watermelon falls with constant
acceleration
the universal gravitational constant G was first measured
after newtons time
Your friend says that the heavyweight champion of the world cannot exert a force of 50 N on an isolated piece of tissue paper with his best punch. You
agree its cant be done
a ball thrown in the air will never go as far as physics ideally would predict because
air friction slows the ball
we do not observe tides in a community swimming pool because
all parts of it are practically the same distance from the moon
science, art, and religion normally need not contradict one another because
all three involve different domains
action and reaction pairs of forces
always act simultaneously
in the absence of air friction, the vertical component of a projectile's velocity doesn't change as the projectile moves.
always false
no force due to earths gravity acts on astronauts inside the orbiting space station
always false
energy is changed from one form to another with no net loss or gain
always true
at equilibrium on a bathroom weighing scale, the downward pull of gravity on you is balanced by
an upward support force
An archer shoots an arrow. Consider the action force to be the bowstring against the arrow. The reaction to this force is the
arrows push against the bowstring
the force with which Earth pulls on the Moon is
equal in magnitude to the force that Moon pulls on Earth
a firecracker bursts while freely falling. The combined momentum of its fragments
equals the momentum of the firecracker at the time of burst
a moving van with a stone lightly glued to the midpoint of its ceiling smoothly moves at a constant velocity. When glue gives way the stone falls and hits the floor
exactly below the midpoint of the ceiling
when a rocket forces exhaust gases downward, the exhaust gases
exert an upward force on the rocket
science later greatly advanced when Galileo favored
experiment over philosophical discussions
an earth satellite in an elliptical orbit travels the slowest when it is
farthest fro earth, near apogee
according to kepler, the speed of a planet is slowest when it is
farthest from the sun
when you drop a rubber ball on the floor it bounces back. The force exerted on the ball to produce bouncing is by the
floor
Whirl a rock at the end of a string and it follows a circular path. If the string breaks, the tendency of the rock is to
follow a straight line path
the newton is a unit of
force
a player hits a ball with a bat. if action is the force of the bat against the ball reaction is the
force that exerts on the bat
in physics work is defined as
force x distance
a bicycle that travels twice as fast as another when braking to a stop will skid
four times as far
the work you do when pushing a shopping cart twice as far while applying twice the force is
four times as much
two identical golf carts move at different speeds. The faster cart has twice the speed and therefore has
four times the kinetic energy
an earth satellite is simply a projectile
freely falling around the earth
When any object is thrown upward, neglecting air resistance, the acceleration along its path is
g downward
the first scientist to introduce the concept of inertia was
galileo
as water drops fall at a steady rate from a leaking faucet they
get farther apart
only the mass of one interacting planet is doubled
gravitational force = doubled
The distance between two interacting planets is tripled
gravitational force = one ninth
The distance between two interacting planets is halved.
gravitational force = quadrupled
the masses of two interacting objects are both doubled
gravitational force = quadrupled
The distance between two interacting planets is doubled
gravitational force = quartered
The distance between two interacting planets is one-fourth.
gravitational force = x16
Suspend your body from a pair of ropes slightly angled from the vertical, and the tension in each rope will be
greater than half your weight
after rolling halfway down an incline, a marble's kinetic energy is
greater than its potential energy
according to Newton, the greater the masses of interacting objects, the
greater the gravitational force between them
An object that has kinetic energy must be
moving
to produce an acceleration to a system there
must be a net force on the system
horses with the greatest linear speed on a merry-go-round are located
near the outside
the amount of gravitational force that acts on the space shuttle while in orbit is
nearly as much as the vehicles weight on earths surface
acrobat Bart at the circus drops vertically onto the end of a see-saw, with his partner Art equidistant from the fulcrum at the other end. Art is propelled straight upward a distance twice that of Bart's dropping distance. neglecting inefficiencies we see
need more information
A small economy car (low mass) and a limousine (high mass) are pushed from rest across a parking lot, equal distances with equal forces. the car that receives the more kinetic energy is the
neither one- they receive the same amount of kinetic energy
If you drop a feather and a coin at the same time in a vacuum tube, which will reach the bottom of the tube first?
neither they will reach the bottom at the same time
the best time for digging clams (when the low tide is extra low) is during the time of the
new or full moon
a 400N person has fallen into a tunnel and is stuck in the center of the earth
new weight = 0N
A 500-N person is standing on a planet where the mass of the planet has doubled, but it's radius has stayed the same.
new weight = 1000N
A 400-N person is sitting on a ladder one Earth-radius length above the Earth.
new weight = 100N
a 400N person has fallen into a deep hole that is 1/2 the radius of the earth
new weight = 200N
A 500-N person on a space ship travels a distance of 4 times the Earth's radius above the Earth.
new weight = 31.25 N (1/16 x 500 N)
a 600N person is standing on the surface of the earth
new weight = 600N
An object's weight is properly expressed in units of
newtons
a gymnast performing somersaults in a high flying plane moving at constant velocity needs to make
no adjustments
which of these vary for satellites in elliptical orbits
none of the above
Two planets in space gravitationally attract each other. If both the masses and distances are doubled, the force between them is
none of the answers are correct
if the sun becomes twice as massive your attraction to the sun would double and your weight measured on earth would
not change
An object will fall over if its center of gravity is
not over its area of support
what prevents satellites such as the space shuttle from falling
nothing
which objects roll down an incline with the greatest acceleration
objects with small rotational inertia
a hockey puck sliding across the ice finally comes to rest because
of friction
a rocket is able to accelerate in the vacuum of space when it fires its engines. the force that propels the rocket is the force...
of the exaust gases on the rocket
the force of gravity on you is greatest when you are standing
on earths surface
a high school student hits a nail with a hammer. during the collision the is a force
on the nail and also on the hammer
the main reason ocean tides exist is that the moons pull is stronger
on the water closer to it than on water farther away
which rocket would require more fuel
one going from Earth to the Moon
halfway to the center of a planet of uniform density, your weight compared to that at the surface would be
one half
according to newton, when the distance between two interacting objects double the gravitational force is
one quarter
The force of Earth's gravity on a capsule in space will lesson as it moves farther away. If the capsule moves to three times the distance, the force toward Earth becomes
one-ninth
a parallelogram is a four sided figure with opposite sides that are
paralell
speed, acceleration, and kinetic energy is greater for a satellite when it is at the
perigee
a job is done slowly, and an identical job is done quickly. Both jobs require the same amount of work but different amounts of
power
when you walk you push on the left and the floor
pushes you to the right
the period of an earth satellite depends on the satellites
radial distance from earth
which is not a step of the scientific method
recognize a problem
Nellie tosses a ball upward at an angle. Neglecting air resistance, the horizontal component of the initial velocity
remains constant
as soon as a bowling ball rolls off the edge of a table its horizontal component of velocity
remains constant
when a star collapses to form a black hole, its mass
remains the same
according to kepler, the paths of the planets about the sun are
ellipses
a rollerskate at rest may have
energy
an object at rest may have
energy
the unit kilowatt-hour is a unit of
energy
one possible unit of speed is
- mph -light years per century - kilometers per house
An apple at rest weighs 1 N. The net force on the apple when it is in free fall is
0 N
If a car increases its velocity from zero to 60 m/s in 10 seconds, its acceleration is
6 m/s^2
a 10 kg brick and 1 kg apple are dropped in a vacuum. the force of gravity on the brick is
10x more than the force on the apple
the unit for work is the
joule
a pencil lies on your desk if the earth is moving around the sun at a speed of 30 km/s how fast is the pencil moving relative to the desk how fast is the pencil moving relative to the sun
0 km/s; 30 km/s
A ball is thrown straight up. At the top of its path its instantaneous speed is
0 m/s
a mosquito flying at 3 m/s that encounters a breeze blowing at 3 m/s in the opposite direction has a speed of
0 m/s
An object covers a distance of 8 meters in the first second of travel, another 8 meters during the next second, and 8 meters again during the third second. Its acceleration is
0 m/s^2
Scotty Skydiver of mass 100 kg experiences air resistance of 500 N, and an acceleration of about
0.5 g
An apple weighs 1 N. When the apple is held at rest above your head, the net force on the apple is
1 N
a 1-kg rock is suspended from the tip of a horizontal meterstick at the 0-cm mark so that the meterstick barely balances like a seesaw when its fulcrum is at the 25-cm mark. From this information, the mass of the meterstick is
1 kg
the mass of a pet turtle that weights 10 N is about
1 kg
a 1-kg chunk of putty moving at 1 m/s collides with and sticks to a 5 kg bowling ball initally at rest. the bowling ball and putty then move with a momentum of
1 kg m/s
a 10 kilogram block is pushed across a horizontal surface with a horizontal force of 20 N against a friction force of 10 N the acceleration of the block is
1 m/s^2
the time it takes a projectile fired straight up at 10 m/s to reach the top of its path is about
1 sec
people in the future may well live inside a rotating space structure that is more than 2 km in diameter. Inside the structure, people on the inside of the outer edge will experience 1 g while people halfway to the axis will experience.
1/2 g
a car by itself is capable of a certain maximum acceleration. when it tows a car of the same mass, its maximum acceleration is
1/3
a 5-kg shark swimming at 1 m/s swallows an absent minded 1 kg fish swimming toward it at 4 m/s. the speed of the shark after his meal is
1/6 m/s
A block pulled to the left with 15 N and to the right with 5 N at the same time experiences a net force of
10 N
About 40 J is required to push a crate 4 m across a floor. If the push is in the same direction as the motion of the crate, the force on the crate is about
10 N
a 1 kg ball is thrown at 10 m/s straight upward neglecting air resistance the net force that acts on the stone when it is halfway to the top of its path is about
10 N
a 1kg mass at the earth's surface weighs
10 N
one kg at the earths surface weighs
10 N
the force of friction on a sliding object is 10 N. the applied force needed to maintain a constant velocity is
10 N
the support force on a 10 N book at rest on a table is
10 N
a motorboat that normally travels at 8 km/h in still water heads directly across a 6 km/h flowing river the resulting speed of the boat is about
10 km/h
A ball is thrown straight up. At the top of its path its acceleration is
10 m/s
If a freely falling object were somehow equipped with a speedometer, its speed reading would increase each second by
10 m/s
If you throw a ball straight downward (in the absence of air resistance), after leaving your hand its acceleration is
10 m/s^2
When a ball thrown straight upwards reaches the very top of its path, its acceleration is
10 m/s^2
a rock is thrown vertically into the air. at the top of its path its acceleration is
10 m/s^2
a car accelerates at 2 m/s^2 assuming the car starts from rest how much time does it need to accelerate to a speed of 20 m/s
10 seconds
a push on a 1 kg brick accelerates it. neglecting friction equally accelerating a 10 kg brick requires
10 time as much force
neglecting air resistance, Sammy Smarts on a high ladder releases a ball that strikes the ground with 100 J of kinetic energy. If he were to instead throw the ball straight upward, it will soon reach the ground with a kinetic energy of
100 J
a weight watcher who normally weighs 400 N stands on top of a very tall ladder so she is one Earth radius above the Earth's surface. how much would she weigh there...
100 N
one end of a rope is pulled with 100 N, while the opposite end also is pulled with 100 N. the tension in the rope is
100 N
Phil applies 100 N to a pulley system and raises a load one-tenth of his downward pull. Ideally, the weight of the load is
1000 N
two projectiles are fired from ground level at equal speeds but different angles. one is fired at an angle of 30º and the other at 60º. the projectile to hit the ground first will be the one fired at (neglect air resistance)
30º
suppose the gravitational force between two masses is 70 N. If the magnitude of one of the masses halves, what is the force between the masses?
35 N
A projectile is fired into the air at an angle of 55° above ground level and hits a target downrange. It will also hit the target if fired at an angle of
35 degrees
Two projectiles are fired from ground level at equal speeds but different angles. One is fired at an angle of 35° and the other at 55°. Neglecting air resistance, the projectile to hit the ground first will be the one fired at
35 degrees
what is the acceleration of a car that starts from rest and 5 seconds later reaches a speed of 20 m/s
4 m/s^2
a ball is moving at 6.0 m/s and has a momentum of a 24.0 kg m/s what is the balls mass
4.0 kg
the work done in pushing a TV set a distance of 2 m with an average force of 20 N is
40 J
An 800-N man stands at rest on two bathroom scales so that his weight is distributed evenly over both scales. The reading on each scale is
400 N
burl and paul have a total weight of 1300 N the tension in the supporting ropes that supporting ropes that support their scaffold and add to 1700 N the weight of the scaffold itself must be
400 N
a projectile is fired into the air at an angle of 50º above ground level and hits a target downrange. it will also hit the target if fired at an angle of
40º
a person is attracted towards the center of the earth by a 440 N gravitational force. the force with which earth is attracted toward the person is
440 N
in the absence of air resistance the angle at which a thrown ball will go the farthest is
45º
a humming bird flying at 4 km/h that gets caught in a 3km/h crosswind has a resultant speed of about
5 km/h
it there were no gravity a stone thrown upward at 45 degrees would follow a straight-line path. but because of gravity, at the end of 1 second, the stone is actually
5 m below the straight line
a 5-kg fish swimming at 1 m/s swallows an absent minded 1 kg fish at rest. the speed of the larger fish after lunch is
5/6 m/s
a jack system will increase the potential energy of a heavy load by 1000 J with a work input of 2000 J. The efficiency of the jack system is
50%
Joshua is attracted toward Earth by a 500-N gravitational force. The Earth is attracted toward Joshua with a force of
500 N
Suzie Skydiver, who weighs 500 N, reaches terminal velocity of 90 km/h. The air resistance on Suzie is then
500 N
what is the force of gravity on a 500 N woman standing on earths surface
500 N
danny diver weighs 500 N and steps off a diving board 10 m above the water. danny hits the water with kinetic energy of
5000 J
Jason weighs 150 N and sits on his big brother's shoulders. Big brother weighs 400 N. The support force supplied by the floor must be
550 N
a 10 N falling object encounters 4 N of air resistance, the net force on the object is
6 N
the power required to exert a 4N force over 3 meters in 2 seconds is
6 W
the change in momentum that occurs when a 1.0 kg ball traveling at 4.0 m/s strikes a wall and bounces back at 2.0 m/s is...
6 kg m/s
A 2-kg ball is thrown at 3 m/s. What is the ball's momentum?
6 kg x m/s
a 5000-kg freight car collides with a 10,000 kg freight car at rest. they couple upon collision and move at 2 m/s. what was the initial speed of the 5000 kg car
6 m/s
a mosquito flying at 3 m/s that encounters a breeze blowing at 3 m/s in the same direction has a speed of
6 m/s
a baseball is hurled into the air at an angle of 30 degrees above the horizontal and lands on a target that is at the same level as that where the baseball started. the baseball will also land on the target if it is thrown at an angle of.
60º
how much force is needed to accelerate a 4.0 kg physics book to an acceleration of 2.0 m/s^2
8.0 N
an 80km/h airplane flying in the same direction as a 10km/h tail wind has a groundspeed of...
90 km/h
the amount of force needed to sustain motion of a rock in outer space
A. a force equal to its weight B. a force less than its weight if friction is absent Answer: NONE OF THESE
Two balls are projected horizontally from a lab bench. One travels at 2m/s, the other at 4 m/s. Which ball will be in the air the longest? Which will hit the ground first?
Both balls will be in the air the same amount of time and both balls will hit the ground at the same time.
a ball is thrown into the air at some angle. at the very top of the ball's path, its velocity is
entirely horizontal
the net force on any object in equilibrium is
zero
A bullet is fired 10 degrees above the horizontal while another bullet is simultaneously dropped from the level of the rifle. Which bullet will hit the ground first?
The dropped one will hit first. In the other examples, both projectiles were level, in this case one bullet is aimed at 10 degrees above the horizon, so it has to go up before it goes down.
A bullet is fired 10 degrees below the horizontal while another bullet is simultaneously dropped from the level of the rifle. Which bullet will hit the ground first?
The one fired.
A ball is tossed upward. Assuming no air resistance, which component of velocity changes with time and which does not?
The vertical component changes while the horizontal component does NOT change.
according to kepler, the path of planets about the sun are
ellipses
when the sun shines on the moon the moon casts a shadow
at all times that is tapered that sometimes falls on earth
Neglecting friction, a small and a large block of ice begin sliding down an incline together. The larger block reaches the bottom
at the same time as the small block
earth satellites are typically more than 100 km high so as to be above earths
atmosphere
which of these is a scientific hypothesis
atoms are the smallest particles of matter that exist
you're driving down the highway and a bug spatters into your windshield. Which undergoes the greater change in momentum during the time of contact?
both the same
Arnold Strongman and Suzie Small each pull very hard on opposite ends of a massless rope in a tug-of-war. The greater force on the rope is exerted by
both the same interestingly
the greater efficiency achieved with the curved blades
bouncing
to make a profit a buyer purchases metal by weight at one altitude and sells it at the same price per pound at another altitude. the supplier should
buy at a high altitude and sell at a low altitude
a cannon recoils from launching a cannonball. the speed of the cannons recoil is small because the
cannon has far more mass than the cannonball
An object thrown into the air with a spin rotates about its
center of gravity
the long, heavy tail of a spider monkey enables the monkey to easily vary its
center of gravity
centripetal force does no work on a circularly moving object because
centripetal force has no component in the direction of motion
If an object moves with constant acceleration, its velocity must
change by the same amount each second
a coin and a ring roll down an incline starting at the same time. The one to reach the bottom first will be the
coin
Eratosthenes first learned about the position of the Sun in mid-summer by
consulting library information
If no external forces act on a moving object, it will
continue moving at the same speed
suppose a particle is accelerated through space by a 10-N force. suddenly the particle encounters a second force of 10-N in a direction opposite to that of the first force. the particle..
continues at the speed it had when it encountered the second force
the first scientist to be credited for postulating that Earth circled the Sun was
copernicus
when you do somersaults, you'll more easily rotate when your body is
curled up into a balled shape
if Earth's mass decreased to one-half its original mass with no change in radius, then your weight would
decrease to half
Rockets are launched from an airplane in the forward direction of motion. The kinetic energy of the airplane will be
decreased
When the angle of an incline with a block resting on it increases, the normal support force
decreases
while a rock thrown upward at 50 degrees to the horizontal rises, neglecting air drag, its vertical component of velocity
decreases
the normal force that acts on a block of ice that slides on a ramp
decreases as the slope of the ramp increases
nellie tosses a ball upward at an angle. neglecting air resistance, the vertical component of the initial velocity
decreases with time to reach the top
when Burl and Paul stand on opposite ends of a sign-painting scaffold, the tensions in the supporting ropes
depend on the relative weights of burl and paul
a car travels in a circle with constant speed. the net force on the car is
directed toward the center of the curve
the net force exerted on a car traveling in a circular path at constant speed is
directed toward the center of the curve
while an airplane flies at 40 m/s at an altitude of 500 meters, the pilot drops a heavy package that falls to the ground. neglecting air drag, about where does the package land relative to the plane flying above
directly beneath the plane
the two measurements necessary for calculating average speed are
distance and time
while you stand on the floor you are pulled downward by gravity, and supported upward by the floor. gravity pulling down and the support force pushing up...
do not make an action reaction pair of forces
a tightrope walker more easily balances on a tight wire if her pole
droops
if an object is placed exactly halfway between earth and the moon, it would fall toward the
earth
for all paths of Earth satellites, one focus of the path is
earths center
consider a moon that orbits one of our most distant planets in an elliptical path. the distance that the moon covers each day is
greatest when closest to the planet
a clerk can lift cylindrical packages 1 meter vertically, or can roll them up a 2-meter-long ramp to the same elevation. with the ramp, the applied force required is about
half as much
When Nellie Newton hangs by the ends of a rope draped over a large pulley, the tension in each supporting vertical strand is
half her weight
Suspend your body from a pair of vertical ropes and the tension in each rope will be
half your weight
when Monkey Mo is suspended at rest by holding a rope with one hand and the side of his cage with the other, all the force vectors that act on him
have a vector sum of zero
a skydiver's terminal velocity will be greatest if she falls
head first
when Joshua brakes his speeding bicycle to a stop, kinetic energy is transformed to
heat
Two objects of the same size, but unequal weights are dropped from a tall tower. Taking air resistance into consideration, the object to hit the ground first will be the
heavier object
the lift experienced by a helicopter involves an action- reaction pair of forces between the..
helicopter blades and the air
in order for a satellite to have an elliptical orbit it must have a speed _______ than 8 km/s
higher
nellie newton swings a rock into a circular path while holding an attached string overhead. The string makes a 45-degree angle to the vertical. The centripetal force that holds the rock in its circular path is the
horizontal component of the string tension
nellie's weight and normal force usually have the same magnitude when she stands on a
horizontal surface
a cannonball shot from a long-barrel cannon travels faster than one shot from a short-barrel cannon because the cannonball receives a greater
impulse
If you toss a coin straight upward in train that gains speed while the coin is in the air, the coin will land
in back of you
where is the center of gravity of a softball bat located at
in the more massive end of the bat
a block is at rest on an incline. the force of friction necessary to prevent the block from the incline angle is
increased
If an object's mass is decreasing while a constant force is applied to the object, the acceleration
increases
the distance a freely falling bowling ball falls each second
increases
two objects move toward each other because of gravitational attraction. As the objects get closer and closer, the force between them
increases
when Freddy Frog drops vertically from a tree onto a horizontally-moving skateboard, the speed of the skateboard
increases
when a twirling ice skater brings her arms inward, her rotational speed
increases
An object with twice as much mass as another object has twice as much
inertia
If your automobile runs out of fuel while you are driving, the engine stops, but you do not come to an abrupt stop due to
inertia
One object has twice as much mass as another object. The first object also has twice as much
inertia
the resistance an object has to changes in its rotational state of motion is called rotational....
inertia
which concept is being illustrated when a tablecloth is quickly tanked beneath dishes resting on a table
inertia
the speedometer of an automobile reads
instantaneous speed
what is the direction of the force that acts on clothes in the spin cycle of a washing machine
inward
If the net force on a cart is tripled, the cart's acceleration
is 3 times as much
for every action force there must be a reaction force that
is equal in magnitude
When a basketball player jumps to make a shot, once the feet are off the floor, the jumper's acceleration
is g: no more, no less
the amount of work done on a heavy box carried by Nellie across a room at a constant speed
is none
what happens to KE when the potential energy of a satellite decreases
it increases
when potential energy of a satellite decreases
its kinetic energy correspondingly increases
the early bird communication satellite hovers over the same point on earth's equator indefinitely because
its orbital period is 24 hours
a single brick falls with acceleration g. the reason a double brick falls with the same acceleration is
its ratio of force to mass is the same
the tangential velocity of an earth satellite is
its velocity parallel to the surface of the earth
A rock is thrown vertically into the air. At the very top of its trajectory the net force on it is
its weight
the planet jupiter is about 300 times as massive as earth, yet on its surface you would weigh only 3 times as much because
jupiters radius is about 10 times earths radius
Galileo taught us that if you roll a ball along a level surface it will
keep rolling if friction is absent
an unfortunate bug splatters against the windshield of a moving car. compared to the deceleration of the car, the deceleration of the bug is
larger
padded dashboards in cars are safer in an accident than non-padded ones because passengers hitting the dashboard encounter
lengthened time of contact
a ball is thrown vertically into the air. because of air resistance, its speed when it returns to its starting level compared with its initial speed is
less
ideally, a ball is thrown up at an angle and lands downrange. Because of air resistance, the distance reached is
less
a large heavy truck and a small baby carriage roll down a hill. neglecting friction, at the bottom of the hill, the baby carriage will likely have
less momentum
a piece of putty moving with 1 unit of momentum strikes and sticks to a heavy bowling ball that is initially at rest. both move with a combined momentum of
less than 1 unit
a lunar month is about 28 days. if the moon were closer to the earth than it is now, the lunar month would be
less than 28 days
a heavy block at rest is suspended by a vertical rope. when the block accelerates upward by the rope, the rope tension is
less than its weight
a pair of toys freight cars one twice the mass of the other, fly apart when a compressed spring that joins them is released acceleration will be greater for the
lighter car
a weightless astronaut in an orbiting satellite is
like the satellite, pulled by Earth's gravitation
an object has gravitational potential energy due to its
location
as the polar icecaps melt, the resulting water spreads over the entire Earth. This new mass distribution tends to make the length of a day
longer
stand a meter-stick on its end and let go and it rotates to the floor. If you attach a heavy weight to its upper end and repeat, falling time will be
longer
a kilogram is a measure of an objects
mass
each of us weighs a tiny bit less inside the ground floor of a skyscraper than we do on the ground away from the skyscraper because the
mass of the building above slightly attracts us upward
the momentum of an object is defined as the objects
mass times its velocity
a primary difference between momentum and kinetic energy is
momenta can cancel; kinetic energy cannot
an object that has kinetic energy must have
momentum
if the speed of a motor scooter doubles which of the following also doubles
momentum
which is most responsible for earths ocean tides?
moon
the moon does not crash into earth because
moon has a sufficient tangential speed
a golf ball moving forward with 1 unit of momentum strikes and bounces backward off a heavy bowling ball that is initially at rest and free to move. the bowling ball is set in motion with a momentum of
more than 1 unit
If a monkey floating in outer space throws his hat away, the hat and the monkey will both
move away from each other but at different speeds
which pulls on the oceans of earth with greater force
sun
superman is at rest in space when he throws an asteroid that has more mass than he does. which moves faster, superman or the asteroid
superman
The total momentum of a flock of identical birds could be zero only if the birds are
taking off from the ground
what did newton discover
that gravity was universal
Which has greater kinetic energy, a car traveling at 30 km/h or a half-as-massive car traveling at 60 km/h
the 60 km/h car
a ring, a disk, and a solid ball having equal masses roll down a hill at teh same time. which reaches the bottom first
the ball
when a tennis racquet hits a ball,
the ball hits the racquet
a ball rolling down an incline has its maximum kinetic energy at
the bottom
When a cannonball is fired from a cannon, which undergoes the greater acceleration?
the cannonball
Suppose you accidentally drive into a tree. Which of the following correctly describes the interaction between your car and the tree?
the car and the tree mutually exert equal and opposite forces on each other
If you drop a feather and a coin at the same time in a tube filled with air, which will reach the bottom of the tube first?
the coin
the force that accelerates a rocket in outer space is exerted on the rocket by the
the exhaust gases
no work is done by gravity on a bowling ball that rolls along a bowling alley because
the force on the ball is at right angles to the balls motion
which has more momentum, a large truck moving at 30 miles per hour or a small truck moving at 30 miles per hour
the large truck
Strange as it may seem, it is just as hard to accelerate a car on a level surface on the moon as it is here on Earth because
the mass of the car is independent of gravity
the reason the moon does not fall into earth is that
the moon has a sufficiently large orbital speed
the centripetal force exerted on the stunt motorcyclist Biker Bob while riding on the inner vertical surface of a circular track is
the normal force
a hunter on level ground fires a bullet at an angle of 10 degrees above the horizontal while simultaneously dropping another bullet from the level of the rifle. which bullet will hit the ground first
the one dropped
a hunter on level ground fires a bullet at an angle of 10 degrees below the horizontal while simultaneously dropping another bullet from the level of the rifle. which bullet will hit the ground first
the one fired
A rock weighs 30 N on Earth and another rock weighs 30 N on the Moon. Which rock has the greater mass?
the one on the moon
the fastest moving planet in a solar system is the
the planet nearest the sun
acceleration is defined as
the rate at which velocity itself changes
a black hole is
the remains of a giant star that has undergone gravitational collapse
a table tennis ball launcher is fired. compared to the force on the ball, the force on the launcher is
the same
an object is dropped and falls freely to the ground with an acceleration of g. If it is thrown upward at an angle instead, neglecting air drag the acceleration along its path will be
the same
an unfortunate bug splatters against the windshield of a moving car. Compared to the force of the car on the bug, the force of the bug on the car is...
the same
aunt minnie throws a rock downward, and air resistance is negligible. compared to a rock that is dropped, the acceleration of the rock after it is thrown is
the same
a karate expert executes a swift blow and breaks a cement block with her bare hand. the magnitude of the force on her hand is
the same as the force applied to the block
in order to catch a ball, a baseball player moves his or her hand backward in the direction of the ball's motion. doing this reduces the force of impact on the player's hand principally because
the time of impact is increased
nellie tosses a ball upward at an angle. assuming no air resistance, which component of velocity changes with time
the vertical component
which has more rotational inertia, a bicycle wheel or a solid disk of the same mass and diameter
the wheel
the amount of potential energy possessed by an elevated object is equal to
the work done in lifting it
to say there is no such thing as only one force means
there must also be a corresponding reaction force
Galileo found that a ball rolling down one inclined plane would roll how far up another inclined plane
to nearly its original height
an asteroid exerts a 360-N gravitational force on a nearby spacecraft. the 360 N force on the space craft is directed
toward the asteroid
a freight train rolls along a track with considerable momentum. if it rolls at the same speed but has twice as much mass its momentum is
twice
two identical arrows, one with twice the kinetic energy of the other, are fired into a bale of hay. compared with penetration of the slow arrow, the faster arrow penetrates
twice as far
A crate of grapes lifted 10 meters gains 200 J of potential energy. If the same crate is instead lifted 20 meters, its gain in potential energy is
twice as much
a planet has half the mass of the earth and half the radius. compared to its weight on earth an apple on this planet would weigh
twice as much
compared to a sports car moving at 30 miles per hour, the same sports car moving at 60 miles per hour has
twice as much momentum
a 1000-kg car and a 2000-kg car are hoisted to the same height. Raising the more massive car requires
twice as much work
if you place a pipe over the end of a wrench trying to rotate to rotate a stubborn bolt, effectively making the wrench handle twice as long, you'll multiply the torque by
two
when Kepler devised his laws of planetary motion, he was most influenced by
tycho brahe
You cannot exert a force on a wall
unless the wall simultaneously exerts the same amount of force on you
acceleration is defined as the change in
velocity divided by the time interval
As an object falls freely in a vacuum, its
velocity increases
which of the following is not true about aristotle's concept of violent motion
violent motion is thought to be either straight up or straight down
to rotate a stubborn screw, it is best to use a screwdriver that has a
wide handle
which tin can will roll down an incline in the shortest time, one filled with water or one filled with ice? (Hint: water 'slides' inside the can.)
with water
all simple machines ideally work on the principle that
work input equals work output
For a scientific hypothesis to be valid, there must be a test for proving it
wrong
is a satellite coasting at a constant speed in a circular orbit accelerating?
yes, speed may be constant, but the direction is changing
earth continually moves about 30 km/s through space, which means the wall you stand next to also is moving at 30 km/s. When you jump vertically, the wall doesn't slam into you because
you're moving horizontally just as fast as the wall
while you are standing in the aisle of a bus, the driver suddenly makes a left turn. you lurch to the right due to...
your tendency to keep moving forward
suppose you are in a car that is going around a curve. the speedometer reads a consant 30 miles per hour what is not true
your velocity is constant
When a falling object has reached its terminal velocity, its acceleration is
zero
recoil is noticeable if you throw a heavy ball while standing on roller skates. If instead you go through the motions of throwing the ball but hold onto it, your net recoil velocity will be
zero