PHYSICS 171 Final Exam study guide
Any force, or combination of forces, that causes an object to have a centripetal acceleration is termed a_____ force
centripetal
The change in velocity is a vector that is added to the _____ to produce the final velocity.
initial velocity
Which of the following Greek letters are used to represent different aspects of rotational motion?
α θ ω
A car traveling 30 m/s slows down to 10 m/s in 5 seconds. The car's average acceleration is _______m/s2.
-4
While on a roller coaster ride, a rider goes through a loop. The rider never leaves her seat during the loop. The rider is still in contact with her seat, which means there must be a normal force directed_____ on her when she is upside-down at the highest point in the loop.
down
Two children of different weights are trying to balance a teeter-totter on a playground. The larger child needs to sit _________to the fulcrum than the smaller child in order to balance the teeter-totter.
closer
A figure skater starts to spin with arms extended, then pulls their arms in. Doing this ______.
decreases their moment of inertia increases their rotational velocity their rotational momentum remains constant
If there is a net force acting on an object there will be an acceleration which means that either the speed, the ______ of motion, or both will change.
direction
If you are told that your friend has made 7 revolutions on the merry-go-round, you are being told your friend's rotational
displacement
The angle that something rotates during its motion is called its rotational ________ It is often measured in either degrees, revolutions or radians.
displacement
A child sitting on a merry-go-round has her father double the rotational velocity. At her new rotational velocity, her linear speed is _________what it was prior to being sped up.
double
What does the magnitude of a centripetal force depend on?
Speed Radius of curvature Mass
A ball thrown upward at 20 m/s will have a momentum in the______ direction.
upwards
A box being pushed by a force results in an acceleration of 2 m/s2. The force is then halved, resulting in an acceleration of _______m/s2.
1
A ball is projected horizontally from a table that is 1 m high with initial velocity v0 = 10 ms. At the time it hits the ground, 0.45 s after being launched, the ball will have moved horizontally a distance x = ______m. (Round your answer to the tenths place.)
4.5
If an object is dropped from a height of 10 m, which of the following statements are true?
At any point during the fall, neither the velocity nor acceleration depends on the mass of the object.
In which situations could there be some acceleration?
Changing speed Changing velocity Constant speed
A child dropped a light pencil and a heavy book at the same time from a balcony. Assuming that acceleration of gravity equals 10 m/s2, which of the following is correct? (Ignore air resistance.) Multiple choice question.
In 3 seconds, both the book and the pencil will have the same speed.
The rotational momentum, L, is
Iω
Which quantities are important when trying to balance a scale?
The distance of the masses from the fulcrum. The weight of the masses.
The Sun also exerts a force on the moon as it orbits the Earth. What is the shape of the moon's orbit?
The orbit is a distorted ellipse.
Voyager 1 is a space probe launched by NASA in 1977 and is the farthest human-made object. It experiences negligible gravity. Voyager 1 is propelled by thrusters but will run out of fuel by 2040. What will happen to Voyager 1 after this date?
The velocity of Voyager 1 will remain unchanged. Voyager 1 will continue moving with the speed it will have when the fuel runs out.
For momentum to be conserved, the net external force on the system must be
0
Two massive objects feel a gravitational pull between them. If one of the object's mass is doubled, then the force of gravity between the two objects will be ______times larger.
2
The adjoining graph shows the velocity vs time of a go-kart. At which time(s) is the go-kart at rest?
2 seconds 8 seconds
A car is traveling at a velocity of 30 m/s. The car then starts to accelerate at 5 m/s2. In the 4 seconds the car is accelerating, it gained ______m/s.
20
You push on a wall with 20 N of force to the right. You feel the wall pushing back on you with a force of_______ N leftwards (take the left direction as positive).
20
A disk is initially spinning with a rotational velocity of 6 rad/s. The disk's rotational velocity is increased to 14 rad/s over a 2 second interval. The rotational acceleration during that two second time interval was _______rad/s2.
4
An object spinning in a circle with a constant speed results in some centripetal acceleration. If the speed is doubled, the centripetal acceleration will be______ times what it was.
4
A ball is falling to the Earth. Ignoring air resistance, which of the free-body diagrams shown in the figure is the correct diagram for the ball?
A
Newton's second law contains in it all the information of Newton's first law. However, Newton's first law is simpler; thus, using the first law instead of the second can simplify an analysis. Which of the following situations are best understood using Newton's first law of motion, and not Newton's second law of motion.
A parked car A car traveling in a straight line on cruise control
In which of the following situations is there a normal force acting on the object?
A sitting student A car on the highway A roller coaster car
When you throw a ball straight upward, the ball stops momentarily before it reverses direction and falls down. Which of the following is correct?
As the ball goes up and down, the acceleration is constant and is always pointing down. At the maximum height, the velocity is zero. The velocity of the ball decreases then increases.
Albert and Bob decide to have a swimming race in which they will swim from one end of the pool to the other and back again. Bob completes the race first, ending up back at the start. Albert gets to the other end of the pool the fastest. Choose the true statement below.
Bob has the greater average speed but Albert has the greater average velocity. (Because Bob covered the most distance in the time of the race, his speed is the greatest, but because Albert travels in a specific direction towards the end of the pool, Albert's velocity is greater.)
A car traveling in a straight line has a constant acceleration of 3 m/s2. Based on this information, which of the following statements below is correct?
Every second the car will change its speed by 3 m/s. The car will change its speed by 1 m/s in a third of a second. The car will change its velocity by 6 m/s after 2 seconds.
Which of the following are real forces?
Friction force Normal force Gravitational force
When you look at the face of an analog watch (one with hands rotating around the face) the direction of the angular velocity vector of the quick moving second hand is in which direction.
From the face of the clock away from your face.
Whether you throw a ball upward or downward
Its acceleration is always pointing downward.
The graph shows how the velocities of four objects change with time. Select the motions that involve acceleration.
Object 4 between 2 seconds and 13 seconds Object 1 between 2 seconds and 6 seconds Object 2 between 12 seconds and 18 seconds
Object A is thrown straight up with an initial velocity of 10 m/s and object B is thrown straight down with an initial velocity of 5 m/s. Select all the options which accurately describe the situation after 2 seconds.
Object A will have a lower velocity than object B. Both objects will have changed their velocities by the same amount. Both objects will be traveling downward.
When a curved road is banked, which force or component of a force acts as the centripetal force?
The horizontal component of the normal force
Which of the following quantities are vectors?
Velocity Δv Acceleration
Kepler found that the model that matched Tycho Brahe's data the best was where the planetary orbits were elliptical with the sun at one _______of the ellipse.
focus
According to Galileo, an object will not stop moving unless _______is applied to the object.
force
A model of the universe in which the sun is the center is called a______ model and was proposed by Nicolaus Copernicus.
heliocentric
The net force acting on an object multiplied by the time that force acts is called the
impulse
The magnitude of a centripetal force acting on an object is the object's centripetal acceleration, v2r, times the object's
mass
The hunter aimed at the monkey with his blowgun and fired at the same instant as the monkey released its grip on the branch. The hunter will hit the monkey
regardless of whether the monkey was light or heavy.
If an object has zero net force acting on it, then the object
remains at rest. must travel at constant velocity. must travel at constant speed. must travel in a straight line.
The _______of an object to changing its state of rotational motion is called an object's rotational inertia.
resistance
Choose which of the following are units of rotational displacement.
revolutions radians degrees
In an elastic collision both kinetic energy and momentum are conserved. Conservation of momentum requires the momentum vectors to form a triangle. Conservation of kinetic energy forces the triangle to be a ______ triangle
right
Two objects collide, one moving quickly to the______ and the other at rest. After the collision, the two objects stick together and the whole system moves to the right, since the net external force was zero.
right
The quantity that describes how fast an object is rotating through some angle is ______ velocity
rotational
Because Newton's law of Universal Gravitation depends on the distance between the centers of two objects, you would expect g, the acceleration due to gravity, to be______at the top of a very high mountain than at sea level.
smaller
Two football players of equal mass, one traveling south and the other traveling west, collide and stick together. The momentum of the two players will be _____.
some westward some southward
The centripetal acceleration is proportional to the _____square of the and inversely proportional to the______ of the curve.
speed radius
Two connected carts are pulled across the floor under the influence of a force F. Which of the following is true?
treat the motion of the individual carts separately. Treat the two carts as a single system to find the acceleration.
The ball is initially accelerated downward by the gravitational force. When it reaches the floor, its ______quickly changes in direction, and the ball heads back upward.
velocity
Which equation would be good to find how long an object had been rotating if you knew the rotational acceleration, the rotational displacement, and that the object had started from rest?
θ=ωit+12αt2
You are standing next to a cliff and throw a ball straight upward with an initial velocity v0 = 30 m/s. After 7 seconds, the ball will be at a height of ____ m. Use g ≈ 10 m/s2 pointing down and take the point from which you throw the ball as the reference.
-35
The orbital period of the moon depends primarily on the mass of the
Earth
Identify the true statements of a planet orbiting the sun.
It is having a force acting centripetally. It is having a centripetal acceleration.
True or false: The acceleration due to gravity is the same for all objects (ignoring air resistance) regardless of their mass.
T
The gravitational acceleration on the surface of the moon is smaller than on the surface of Earth. Choose all the reasons that contribute to this.
The mass of the moon is smaller than that of Earth. The radius of the moon is smaller than that of Earth.
Which of the following statement is true about the acceleration of a body?
The shorter the time for a given change in velocity, the larger the acceleration and the force needed to produce this change.
If the velocity of an object is changing, the object must be
accelerating
A tire rotating at constant rotational velocity has zero rotational __________since the rotational velocity is not changing.
acceleration
To increase the impulse on an object someone could
apply the force for a longer time increase the applied force
A car traveling at 20 m/s eastward will have a momentum in the ______ direction
eastward
A puck slides along a frictionless surface in the northward direction. An eastward impulse is applied to the puck. The change in momentum of the puck is in the_______ direction
eastward
When a rocket exhausts some gas during propulsion, the momentum of the exhaust gas must equal the momentum of the rocket. This is because they exert ______ and ______ forces due to Newton's third law.
equal opposite
When a marble launcher shoots a marble, the recoil velocity of the launcher can be reduced by_____ the mass of the launcher.
increasing
A piece of al dente pasta is thrown against the wall to see if it is cooked. Being cooked, the noodle sticks to the wall after its perfectly __________ collision.
inelastic
A person holding weights, out away from their body, slowly spins on a rotating chair with negligible friction from the bearings. When they bring their arms in, the chair speeds up and spins faster. This occurs because the total rotational __________must remain constant.
momentum
In real-world collisions, the net force is rarely exactly zero; however, conservation of_________ may still be used since the external forces on the system are much smaller than the forces involved in the collision.
momentum
The amount of motion (or quantity of motion) of an object is its
momentum
The product of the rotational velocity with the moment of inertia is the rotational
momentum
In order for an object to travel in a circle, even at constant speed, there must be a ______ force acting on the object.
net
The phase of the moon shown in position 1 of the figure is called a _____ moon.
new
The sun exerts a force on the moon that distorts the moon's orbit causing the moon's orbit around Earth to
oscillate about a true elliptical path
The sun exerts a force on the moon that distorts the moon's orbit causing the moon's orbit around Earth to _____.
oscillate about a true elliptical path
The quantity that describes how fast an object is rotating through some angle is_______ velocity
rotational
The quantity measuring how far an object has turned or rotated is an angle, often called the
rotational displacement
Newton's law of universal gravitation depends on
the masses of the objects. the distance between the objects.
The rotational velocity is the rotational displacement divided by the______it took for the rotational displacement to happen.
time
A car traveling eastwards gains 1 m/s eastwards every second. The car is _____. Choose all that are correct.
changing its velocity changing its speed speeding up accelerating
When driving a car in a straight line, in which situations do you obtain a nonzero acceleration?
When you press down farther on the gas pedal and the speedometer increases (When the speed is increasing, there is a change in the speed so there must be a non-zero acceleration.) When you release the gas pedal a little and the speedometer decreases
A car is traveling at a velocity of 40 m/s. The car then starts to accelerate at --5 m/s2. If the car accelerates for 6 seconds, it loses ______ m/s.
30
A runner traveling at 8 m/s begins to slow down by accelerating at --1 m/s2 for 4 seconds. Without the acceleration the runner would have ran ______m during those 4 seconds, but the acceleration reduced the distance by ________m.
32 8
A rock is dropped over a cliff. At some point in it's fall you measure the speed with a radar gun to be 27 m/s. Exactly 2 second later it is moving at _____ m/s. You may approximate the acceleration due to gravity as being 10 m/s2.
37
Galileo used an inclined plane to slow down the falling motion so that he could measure the acceleration due to gravity. What was his rationale for using the inclined plane?
Along an inclined plane, only part of gravity acts on the object in its direction of motion.
A student driver is having trouble maintaining constant pressure on the pedals and is driving a very "jerky" manner. Arrange the following instances of acceleration from greatest to least in terms of change in velocity. Each change in velocity happens over a 1 second period of time.
5-20 10-20 5-10 39-40
For a book sitting on a table, the acceleration of gravity is equal to ______m/s2
9.8
Newton's ____ law tells us what happens in the absence of a force, and Newton's _____ law describes the effects of applying a force to an object.
first second
An object is definitely accelerating if it is
slowing down. changing velocity. speeding up.
A ball is thrown with an initial angle θ = 30° and an initial speed v1. A second ball is thrown from the same height with an initial angle θ = 45°. If both balls reach the same maximum height, the initial speed of the second ball is Multiple choice question.
smaller than v1.
An apple at rest on a table has two forces acting on it, the normal force and the gravitational force. The reaction force to the gravitational force is
the gravitational force of the apple on the Earth.
A 10-kg box is attached to two strings, each on opposite ends of the box. The string on the right is pulled to the right with a 6 N force while the left string is pulled to the left with 6 N. Due to these pulls, the box experiences an acceleration of_____ m/s2 to the left (take the left direction to be positive).
0
While in a 1000 kg car traveling on cruise control, you are told the air resistance is generating a force of 16000 N against your motion. Your two friends in the back decide they want to accelerate the car, so they push on the seats of the car with 600 N of force each. The change in car's acceleration now becomes _______m/s2.
0
The plot depicts the position versus time of a toy car in one dimension. During which time interval(s) is the car going backward?
0--2 seconds 4--6 seconds
A 10-kg box is attached to two strings, each on opposite ends of the box. The string on the right is pulled to the right with a 6 N force while the left string is pulled to the left with 8 N. Due to these pulls, the box experiences an acceleration of ______m/s2 to the left (take the left direction to be positive).
0.2
A car moves to the right with an initial velocity v0 = 30 ms and an acceleration a = 5 ms2 pointing to the left. After 4 seconds, the car's speed will be______ ms.
10
A car traveling at 20 m/s reaches 60 m/s in 4 seconds traveling in a straight line. The car has an average acceleration of ________m/s2.
10
Fill in the blank question. Consider a rock of mass 20 kg, the weight of the rock on earth is_____ N and the weight of the rock on moon is______ N. Assume the acceleration due to gravity on the surface of the earth is 10 m/s2 and on the moon is 1.6 m/s2.
200 32
An object is projected with an initial angle θ0 = 30°, an initial horizontal velocity v0x = 26ms, and an initial vertical velocity v0y = 15 ms. After 1 second, the object has moved horizontally a distance of _____m and vertically a distance of_______ m. (Use the simplification that g = 10 m/s2.)
26 10.10
The velocity versus time of a toy car is plotted in the adjoining graph. Rank the distance traveled by the car from largest (top) to smallest (bottom) distance for each time interval.
3-6 0-3 6-9
A ball is thrown straight upwards with an initial velocity v0 = 30 m/s. The ball will reach a maximum height of _____ m in _______seconds. Use g ≈ 10 m/s2 pointing downward.
45 3
The plot depicts the position versus time of a toy car in one dimension. During which time interval(s) is the car stationary?
6--8 seconds 0--2 seconds
A ball is projected horizontally from a table 1.0 m high and hits the ground after falling for a time t = 0.45 s. If the ball travels horizontally a distance x = 3.0 m in that time, its initial velocity was equal to_____- m/s.
6.67
two balls are thrown at the same time. One up with initial velocity v0,1 = 30 ms and the other down with initial velocity v0,2 = -30 ms. After 2 seconds, the difference (v1 −v2) of their velocities will be equal to ms (assume that neither ball has hit the ground yet).
60
The velocity versus time graph is for a car traveling in one dimension. During which interval(s) is the car traveling only backward?
8--10 seconds 6--8 seconds
A child drops a soda can from a balcony. The can gains a speed of _____m/s in 8 seconds. (Assume that acceleration of gravity equals 10 m/s2.)
80
If the launch velocity is the same, which launch angle gives the highest peak?
85
Arrange the adjoining velocity versus time plots of four toy cars in order from most distance covered (top) to least distance covered (bottom).
B C D A
A dropped super ball bounces off the ground and comes back up with the same speed. True or false: The ball's velocity just before bouncing was the same as immediately after it bounced.
False Yes, the ball's direction changed, and the velocity depends on speed and direction.
Select the option that explains why Galileo rejected Aristotle's theory describing the motion of falling objects.
Galileo relied on experiments that proved Aristotle wrong. Aristotle's observations did not take all relevant factors (e.g., air resistance) into account.
Which units would be acceptable units of speed?
Miles per hour Centimeters per day Inches per decade
A ball attached to a string is being whirled in a horizontal circle on a frictionless table. The string snaps. The ball then travels in a straight line. Which of Newton's Laws best explains this?
Newton's first Law
Galileo argued that the natural tendency of a moving object is to continue moving and no force is required to maintain this motion.
T
The Earth travels around the sun in an almost circular orbit at an almost constant speed of 107,300 km/h (or 67,062 mi/h)! Which statement(s) are true about the Earth's motion about the sun?
The Earth has a velocity that is always changing. The Earth is accelerating since the direction of its velocity is changing.
A spaceship traveling 100,000 m/s in deep space, not near any other planets or stars, runs out of fuel during its trip. Which of the following will happen?
The spaceship will continue traveling at 100,000 m/s.
An object is thrown straight upward. Select the option that best describes the situation at its maximum height.
The velocity and speed are equal to zero while the gravitational acceleration points down.
A red car has an instantaneous acceleration of 16 m/s2 westwards while a blue car has an instantaneous acceleration of 8 m/s2 westwards. Based on this information, what can be correctly stated about their motion?
We do not know which car is traveling faster.
The gravitational force is proportional to the mass, but by Newton's second law, the_____ is inversely proportional to the mass.
acceleration
We would say Newton's laws are general because they apply to ______objects, not just ones on Earth or just in the sky.
all
While an object is falling, its acceleration will remain ________ , but its velocity will ______ [insert one word into each blank]
constant increase
If you wish to increase an object's acceleration without changing the force on the object,_____ you must the object's mass.
decrease, reduce, lower,
What does a speedometer measure?
Instantaneous speed
An apple is dropped and accelerates towards the ground. What force causes the apple to accelerate?
The gravitational force
To which of the following things would Newton's laws apply?
Planets Rocks on Earth Satellites in space Galaxies Rocks on Mars Airplanes Trucks
Which of the following conditions must be true in order for rotational momentum to be conserved?
τNET = 0
Which equation would be good to find the rotational acceleration if we already knew the initial rotational velocity, the rotational displacement, and the final rotational velocity?
ω2=ωi2+2αθ
Identify the equation to find the angular velocity assuming that the constant rotational acceleration, the time taken, and the initial angular velocity is given.
ω=ω0+αt
The force of gravity is attractive, which makes the lever arm distance zero. Thus, the net torque on a planet due to the sun's gravity is A student holds a spinning wheel horizontally such that the rotational momentum of the wheel is 1 kg m2/s. When the student flips the wheel, so that the rotational momentum of the wheel now points downwards, the rotational momentum of the student is _____.
0
A 4-kg box is pushed by a force along the floor resulting in an acceleration of 6 m/s2. Some stuff is removed from the box, making the box half as heavy (2 kg) as it was. The box is then pushed by the same force, which now results in an acceleration of ______m/s2.
12
A car's tires push on the ground with −150 N of force forward. If the tires do not slip, then the ground pushes on the tires with_____ N of force forward. If there are no other horizontal forces on the 1500 kg car, it will experience an acceleration of_______ m/s2 forward.
150 .1
A heavy mass is held fixed on a rigid rod of negligible mass. The moment of inertia of the mass and rod is found to be 12 kg m2. The heavy mass is then moved closer to the axis of rotation along the rod, so that it is now half as far from the axis of rotation then it was. The moment of inertia of the rod is now____________ kg m2.
3
A heavy mass is held fixed on a rigid rod of negligible mass. The moment of inertia of the mass and rod is found to be 8 kg m2. The heavy mass is then moved farther along the rod so that it is now twice as far from the axis of rotation. The moment of inertia of the rod is now _________ kg m2.
32
If a cyclist needs to maintain the same centripetal acceleration but wants to double the speed in the turn, the radius must become _____times what it was previously.
4
Two massive objects feel a gravitational pull between them. If both of the objects' masses are doubled, then the force of gravity between the two objects will be _____times larger.
4
If a car goes 90 miles in 2 hours, the average speed is_________ miles per hour.
45
if the launch velocity is the same, which launch angle gives the maximum range?
45
Select all motions that involve acceleration.
A car negotiating a curved road, moving with a constant speed. A car speeding up in the positive direction. A car slowing down in the negative direction.
Identify which people are accelerating.
A child on a swing. A driver cresting a hill at constant speed. A couple on a carousel going around at constant speed.
Choose all the situations for which the object is accelerating.
A person rocking in a rocking chair. A boomerang traveling at constant speed around in a circle.
Objects A and B have masses mA and mB, respectively. They are thrown down at the same time from the same height with initial speeds vA = 10 ms and vB = 30 ms. Select all the statements that correctly describes the motion of both objects. Ignore air resistance. Multiple select question.
A plot of velocity changes with time for both masses will show parallel straight lines. The velocity of both masses will increase equal amounts in equal times.
In which of the following situations is the collision inelastic of some type (perfectly or otherwise)?
A snowball hits and get stuck to a person riding a bicycle. The pool cue hits the seven ball on a pool table, but some kinetic energy is lost. A motionless couch seat is struck by a falling, tired, student who comes to rest on the couch.
Angular momentum is directly proportional to which of the following?
Angular velocity. Rotational inertia.
In the figure on the right, there are four sets of momentum vectors for different collisions. Which one is from an elastic collision?
B
A vector must have both _____ and _______
Blank 1: magnitude, size, or amount Blank 2: direction or angle
One ball is thrown straight upward with an initial velocity v0. At the same time, a second ball is launched from the same place with an initial angle θ = 30° and the initial velocity v1. Which of the following is correct?
Both balls will reach the same height if the vertical component of v1 is equal to v0. If the initial angle θ is increased, you will have to decrease the initial velocity to reach the same height.
Two birds are flying in separate straight-line paths in the sky, each with a constant speed of 13 m/s. Which of the following statements must be true based solely on the previous statement? Multiple select question.
Both birds are traveling the same distance per second. Both birds have no change in their velocity.
A hard billiard ball elastically collides with another hard billiard ball of equal mass. Which situation is possible?
The first ball stops and the second ball moves with the same velocity as the first.
Two cars of equal mass traveling with the same initial speed eventually come to rest. The blue car hits a brick wall, while the red car (with its engine off) rolls over some grass for awhile before coming to rest. Which car had the largest impulse applied to it?
Both cars had the same impulse.
A rifle fires a bullet. Which of the objects has the largest magnitude of momentum upon being shot? Assume the external forces are negligible.
Both have the same magnitude of momentum.
Which of the following becomes a significant factor for vehicles that have very large launch projectile velocities?
Curvature of the Earth
A couch is pushed along a floor against friction at a constant velocity. A partial free-body diagram is shown in the figure on the right. Select the missing force from the list at the bottom of the figure.
D
The direction of positive torque is arbitrary. For this question we will use counterclockwise as the direction in which the torque must cause the change in rotation in order for it to be positive; otherwise, the torque is negative. Which of the forces in the picture will produce a negative torque?
D C
The direction of positive torque is arbitrary. For this question, we will use counterclockwise as the direction in which the torque must cause the change in rotation in order for it to be positive; otherwise, the torque is negative. Which of the forces in the picture will produce a negative torque about the fulcrum?
D C F
A skydiver jumps out of a plane and eventually reaches terminal velocity. At different instances of the fall, a free-fall diagram of the forces acting on her is shown in the figure. Rank the diagrams in chronological order with the earliest diagram at the top of the list when the diver jumps off the plane.
D A C B
True or false: The vertical component of the normal force exerted by a road on a vehicle can help to produce gravity when the curve is banked.
F
True or false: When a brick and a feather are dropped at the same time from the same height, the brick reaches the floor first because it is heavier; therefore, it has a larger gravitational acceleration.
F
A child dropped a light pencil and a heavy book at the same time from a balcony. Assuming that acceleration of gravity equals 10 m/s2, which of the following is correct? (Ignore air resistance.)
In 3 seconds, both the book and the pencil will have the same speed.
A soccer player who has the ball is being chased by 4 other players from the opposing team. The player with the ball is running east at 20 m/s. Select the opposing player who has the same velocity as the player with the ball.
Number 03 who is running at 20 m/s in the eastward direction.
In which of the following cases would the force of gravity increase by a factor of four?
One of the masses is quadrupled. Both of the masses are doubled. The distance between the objects is halved.
A graph showing a given objects acceleration as it depends on applied force would be a straight line of constant slope. True false question.
T
You throw a ball straight upward with an initial velocity v0 = 30 m/s. Select all the options that correctly describes the motion of the ball. Use g ≈ 10 m/s2 pointing down.
The ball travels the same distance during the first 3 seconds as it does during the next 3 seconds. The ball will travel farther during the 0 to 1 second interval than during the period from 2 to 3 seconds.
In which of the following situations does the car have a nonzero acceleration?
The car starts from rest and speeds up to the speed limit moving in a straight line. The car is traveling at the speed limit, and then it comes to a complete stop in a straight line. The car is on cruise control traveling around a curve. The car is traveling at the speed limit and then comes to a complete stop while traveling around a curve.
Which of these situations will result in the force of gravity decreasing according to Newton's law of universal gravitation?
The distance between the objects doubles One of the object loses half its mass
A hunter with a blowgun saw a monkey hanging in a tree. The hunter aimed at the monkey and fired his blowgun at the same instant the monkey released its grip on the branch. Which of the following is correct? Multiple choice question.
The hunter will hit the monkey provided the distance to the branch is not too great.
During a straight line roller coaster ride, the coaster steadily climbs up a large hill, then rolls down the hill and constantly changes speed as it quickly goes up and down smaller hills until the end of the ride when the coaster slowly comes to a complete stop. Choose the true statement from below.
The instantaneous acceleration will be greatest on the hills during the ride after reaching the top of the first hill.
When you jump into the air, you push off the ground which is to say you exert a force on the Earth. Why doesn't the Earth move? Multiple choice question.
The mass of the Earth is so enormous that the acceleration it experiences is minuscule.
A rocket at rest in outer space fires a burst from its rockets. Which statements are true?
The momentum of the rocket exhaust is equal to the momentum of the rocket. The momentum of the rocket exhaust is equal to the momentum of the rocket. The total momentum after the burst is zero.
A mule pulls a cart twice as heavy as the mule. Which of the following statements are true.
The net force acting on the mule is less than the net force on the cart. The acceleration of the mule is the same as for the cart.
An object is projected with an initial angle θ0 = 30° and an initial velocity v0. Select the option that describes the motion of the object.
The object travels horizontally equal distances in equal times.
Aristotle thought that a thrown object was pushed by the air circulating back to fill the void left by the object and this was the force to keep the object in motion. In a moving car the air is still, but if the driver steps on the brakes loose objects like groceries and books will start to move towards the front of the car. Which answer explains why.
The objects were already in motion with the moving car.
If you wanted to double the linear speed of a child on a merry-go-round, which of the following could you double to accomplish this?
The rotational velocity. The distance from the center.
If scientists wanted to replace an older satellite with a newer, more compact satellite which was 1/8 the mass of the older one, and needed the new one to have the same orbital period, what would its orbital radius be?
The same as the old one.
A canon on rollers fires a canon ball and rolls backward. Which of the following are true statements?
The speed of the canon ball is greater than the canon's speed. The momentums of the canon and canon ball are equal. The force the rocket exerts on the exhaust is equal to the force the exhaust exerts on the rocket. The total momentum after the burst is zero.
Two cars crash into each other and stick together after the collision. Which of the following statements are correct about this collision?
The total momentum after the collision is the same as before the collision. The collision is perfectly inelastic.
A child stands next to a more massive adult on a frictionless frozen pond. The child pushes the adult. Which of the following statements are correct after the push?
The total momentum is zero. The child travels with the greatest speed. Both the child and the adult travel with the same magnitude of momentum.
Two identical steel balls move straight towards each other at the same speed. What happens when they elastically collide with each other?
They both bounce straight back with the same initial speed.
In pine car derbies the official carefully check the weights of each car. Why?
To make sure the gravitational force is similar for each car.
A ball tied to the end of a string is whirled around with a constant speed in a horizontal circle. True or False: the ball is accelerating.
True Reason: Yes, the direction of the velocity is changing (imagine the instantaneous velocity at one point compared with the velocity half a turn later) even if the speed is not.
In which of the following situations is the total momentum always conserved?
When the net force on the system is zero. When all the forces on the system are internal to the system.
A wheel initially rotating at 2 revolutions per second is slowed down to rotate at only 1 revolution per second. During the slowdown the wheel's rotational _________velocity changed, which means it had rotational as well as rotational velocity.
acceleration
The net torque is proportional to the rotational _______The proportionality constant is the moment of inertia.
acceleration
When a ball bounces against a wall there will be large change in velocity in short period of time. This means the ______ is large, hence the net _______ must be proportionately large as well.
acceleration force
The hunter aimed at the monkey and fired his blowgun at the same instant the monkey released its grip on the branch. The hunter will hit the monkey because
both the projectile and the monkey fall down at the same rate.
Newton's laws tell us the planet must have a force to cause the _______acceleration needed to change the direction of the planets. The force that plays this role is gravity.
centripetal
Sometimes interactions are difficult to analyze during the process that causes changes in motion. In these cases it can be easier to describe the overall_________in motion rather than detail it step by step.
change
While on a roller coaster ride, a rider goes through a loop. The rider never leaves her seat during the loop. The rider is still in contact with her seat, which means there must be a normal force directed_____on her when she is upside-down at the highest point in the loop.
down
One of the masses is quadrupled. Both of the masses are doubled. The distance between the objects is halved_______toward the Earth, but the curvature of the Earth's surface results in the moon never hitting the Earth. This shows that at large velocities, the curative of the Earth's surface is important.
falling
The moon does not hover above the Earth because there is no gravity. In fact, the moon is _____toward the Earth, but the curvature of the Earth's surface results in the moon never hitting the Earth. This shows that at large velocities, the curative of the Earth's surface is important.
falling
After a perfectly inelastic collision, the two bodies that collide will have the same _____.
final velocity
A torque is the rotational version of a
force
An object remains at rest, or in uniform motion in a straight line, unless it is compelled to change by an unbalanced, externally imposed
force
When an object is traveling in a circle, its velocity is changing directions. This means there must be some centripetal acceleration. If there is some acceleration, then by Newton's second law, there must be a net
force
A universe model with the Earth at the center, as most early models of the universe speculated, is called a ____model
geocentric
The point in which the weight of the object exerts no torque is called the center of
gravity
Along the trajectory of a projectile, the_____ component of the velocity remains constant, while the ______component changes in both magnitude and direction.
horizontal vertical
The resistance an object has to changing its rotational state is called its rotational
inertia
A rock at rest is dropped from the rooftop of a tall building. The acceleration of the rock is around 10 m/s2 downwards. The distance fallen by the rock during a 1 second time interval is
largest during the last second of falling.
When catching a ball people tend to move their hands backwards with the ball a little bit. Doing so increases the time the hand exerts a stopping force on the ball, which means ________ overall force needs to be applied
less
The equations for rotational motion can be obtained by looking at the equations for ________motion and substituting ________quantities for linear ones.
linear rotational
The moment of inertia, I, of a concentrated mass (the object) at the end of a very light rod depends on the object's _____.
mass distance from the axis of rotation, squared
The momentum of an object depends on its
mass. velocity.
The resistance of an object to change in its rotational motion is its _____.
moment of inertia rotational inertia
A parked car has two forces applied to it, the upward force pushing up on it called____ force and the downward pull is due to gravity.
normal
At the bottom of a Ferris wheel ride the acceleration is straight up. The force that is the largest at this position is the_____ force
normal
All of the original kinetic energy is lost in any _____ collision.
perfectly inelastic
Which of the following would be units for angular acceleration?
rad/s2 rpm/s
The rotational acceleration is the rate of change of the
rotational velocity
According to right-hand rule, if we hold our right hand with fingers curling around the axis of rotation, the thumb would point the direction of _____.
rotational-velocity vector
Identify a commonly used unit for describing the rate of rotation of motors.
rpm
A car starting from rest reaches 45 m/s in 5 seconds. The car has an average acceleration of 9 m/_____.
s/s second per second s2
To find the average speed of an object, we find the change in the distance divided by the time over which that change occurs. For the instantaneous speed, we must make the time interval very, __________so that the speed does not change appreciably.
short, small, brief, abbreviated, terse, little, or tiny
Since the change in the velocity vector is itself a vector it must have a_____ and ______
size direction
Kepler's first law stated that
the planet's orbits were elliptical. the sun was located at one focus of an ellipse.
When a moving bicycle starts to tip over
the rotational momentum of the tipping adds to the rotational momentum of the bicycle.
Which of the following are rotational displacements?
three revolutions four radians thirty-five degrees
The impulse on an object is the multiplication of the _____ multiplied by the _____.
time interval net force
Rotational momentum is conserved when the net _______ on a system is zero.
torque
The center of gravity is a point in which if you put a fulcrum, the weight of the object will give zero
torque
The moment of inertia times the rotational acceleration is equal to the net _________ just like the mass of an object times the acceleration is equal to the net force.
torque
The tendency for a force to produce a rotation is called the
torque
A student holds a spinning wheel horizontally such that the rotational momentum of the wheel is 1 kg m2/s. When the student flips the wheel, so that the rotational momentum of the wheel now points downwards, the rotational momentum of the student is _____.
twice
Galileo wanted to measure the acceleration due to gravity experimentally. For that he
used his own pulse to measure the time. used an inclined plane to slow down the falling motion.
Match the term of the velocity formula and the complete formula with its interpretation. Assume the object is undergoing constant acceleration.
v0 + at =The total velocity at any time. v0 The original velocity of the object when the motion started at The velocity that is gained or lost due to acceleration.
A bullet is shot with an initial velocity v0 and an initial angle θ0 = 45°. Select the correct relationship between the initial components. Multiple choice question. v0x = v0y
v0x = v0y
The change in the rotational displacement in a given time interval is called the rotational
velocity
The rotational momentum of an object is the moment of inertia times the rotational
velocity
The ω symbol is commonly used to represent the rotational ______ while the θ symbol is commonly used for the rotational displacement.
velocity
At the top of a Ferris wheel ride, the centripetal acceleration is straight downwards. The biggest force acting on the rider is the______ force
weight