Physics 10
A package falls off a truck that is moving at 30 M/S. Neglecting air resistance, the horizontal speed of the packages just before it hits the ground is___. a) about 30 M/S b)zero c)less than 30M/S the larger than 0. d) more than 30 m/s e) more information is needed for an estimate
a) about 30 M/S
You're at rest in a hammock when a hungry mosquitoe sees an opportunity for lunch. A mild 2m/s breeze is blowing. If the mosquitoe joins you for lunch it should hover over you by flying___. a) against the breeze at 2 M/S. b) with the breeze at 2 M/S. c) a bit faster than wind speed d) none of the above.
a) against the breeze at 2 M/S.
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 ___. a) agree that it can't be done. b) reserves about this assertion. c) disagree, for a good punch easily delivers that much force.
a) agree that it can't be done.
A large and small person wish to parachute at equal terminal velocities. The larger person should___. a) get a larger parachute. b) jump lightly c) pull upward on the supporting strands to decrease the downward net force. d) jump first from the plane
a) get a larger parachute.
When you weigh yourself on a bathroom scale on a slight incline instead of a level surface, your weight reading on the scale will be___. a) less b) no different c) more
a) less
a ball thrown straight upward takes 10 seconds for it up and down round trip. because of the air resistance, the time take can for the ball just to go up is___. a) less than 5 seconds b) 5 seconds c) more than 5 seconds
a) less than 5 seconds
A bullet has more kinetic energy than the recoiling rifle from which it is fired is because the force on the bullet acts over a A) longer time B) longer distance c) longer time and greater distance
a) longer time
If an object has kinetic energy, then it also must have___. a) momentum b) force c) acceleration d) impulse e) none of the above
a) momentum
The muzzle velocity of a bullet fired from a new rifle is 100m/s. Neglecting air resistance, at the end of one second a bullet fired straight up into the air will have traveled a distance of___. a) (100-5)m b) (100+5) m c) 100 m d) 5 m e) none of the above
a) (100-5)m Note: After 1sec is 90. The average time between 100& 90 is 95.
A woman carries a heavy box across a room at a constant speed. How much work does she do on the box while walking? a) none b) More information is needed about the speed and the distance. c) More information is needed about the weight, distance, and her speed. d) More information is needed about the distance walked.
a) none
While an iron block near the Earth's surface is in free fall, it undergoes an increase in___. a)speed b) acceleration c)both of these d) neither of these
a) speed
As an object freely falls downward its___. a) velocity increases b) acceleration increases c) both of these d) none of these
a) velocity increases
When a falling object has reached its terminal velocity, its acceleration is___. a) zero b)g c) constant
a) zero air resistance=drag
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___. a) 0m/s b)5m/s c)8m/s d)24m/s
a)0m/s
A 2500N pile driver ram falls 10m and drives a post 0.1m into the ground. The average impact force on the ram is___. a)250,000N b)2,500N c)2,500,000N d)25,000N
a)250,000N work done= energy input forced×.1=2500×9.8×10
The pot that falls from a ledge and hits the ground 45 M below, hits the ground at a) 30 m/s b) 60m/s c) 120 m/s d) more than 120m/s.
a)30 m/s Note: Think out side the box. 10m/s =1sec divide each answer with 2. ( x*2=y) Say it drop time was 3 seconds. Then multiple 3 by y. If answer = letter. then it is the correct answer.
Action and reaction pairs of forces___. a) always back simultaneously b) may or may not act simultaneously c) are independent of time
a)always back simultaneously
If no external forces are acting on a moving object, it will___. a) continue moving at the same velocity. b)continue moving at the same speed. c) move slower and slower until it finally stops.
a)continue moving at the same velocity.
Nellie Newton pulls her sled by a rope that is 45 degrees to the horizontal. The horizontal and vertical components of force are___. a) equal in magnitude b) each about .7 times the force are c) both of these d) neither of these
a)equal in magnitude
A pair of air pucks on an air table are set in motion when a compressed spring between them is released. If one puck moves with twice the speed of the other, then its mass is___. a) half the mass of the other. b) the same mass as the other. c) twice the mass as the other d) need more information
a)half the mass of the other.
To produce an acceleration to a system there___. a) must be a net force on the system. b) may or may not be a net force on the system c)must be acceleration outside the system also.
a)must be a net force on the system.
to say there is no such thing as only one force means___. a) there must also be a corresponding reaction force. b) other forces, perhaps not have evident, are there. c) gibberish.
a)there must also be a corresponding reaction force.
Phil leans over the edge of a cliff and throws a rock upward at 5m/s. How far below the level from which it was thrown is the rock 2 seconds later? a) 5m b)10 m c)15m d)20m
b) 10m Note: multiple both numbers together.
The gain in speed each second for a freely falling object is about___. a) 0 b) 10m/s c) 5m/s d) 20m/s e) depends on the initial speed
b) 10m/s
A space habitat is designed so that the variation in g between a person's head and feet is less than 0.01 g. If the person is 2 m tall, then the radius of the habitat is... A. 2000 m B. 200 m C. 20 m D. more than 2000 m
b) 200 m
An 80km/h airplane flying against a 10km/h head wind had a ground speed of___. a) 10 km/h b)70 km/h c)80 km/h d)90 km/h
b) 70 km/h Note: subtract number
When you drop a rubber ball on the floor it bounces back. The force exerted on the ball to produce bouncing is by the___. a) ball b) floor c) need more information
b) floor
Whenever the net force on an object is zero, it's acceleration___. a) may be less than zero b) is zero c) may be more than zero.
b) is zero
two tennis balls fall through the air from a tall building. one of them is filled with lead pellets. The ball to reach the ground first is the___. a) regular ball b) lead-filled ball c) same for both
b) lead-filled ball
A rock is thrown vertically into the air. At the top of its path the net force on it is___. a) less than mg. b) mg c) more than mg.
b) mg
If you push for a half hour or a whole hour against a stationary wall___. a) twice as much work is done during the half hour. b)no work is done in either case c) half as much work is done during the half hour d)it is impossible to determine how much work is done
b) no work is done in either case
The last instant just before an airplane crashes a passenger jumps out of the door and falls only two feet to the ground the passenger is___. a) intelligent I think so fast b) probably hurt or killed c) lucky to have study physics d) unharmed
b) probably hurt more killed
A block of ice sliding down an incline has its maximum speed at___. a) halfway down b) the bottom c) the top d) difficult to predict without knowing the slope of the include e) difficult to predict without knowing the coefficient of friction
b) the bottom
Your weight as measured on your bathroom scale is___. a) equal to your mass b) the force due to gravity on you c) a property of mechanical equilibrium. d) all of the above
b) the force due to gravity on you.
An apple falls from a tree and hits the ground 5 meters below with a speed of about___. a)5 m/s b)10m/s c)15m/s d)20m/s e) not enough information
b)10m/s Note: free fall = 10 m/s
The time it takes a car to attain a speed of 30 m/s when accelerating from rest at 2 m/s^2 is___. a) 2s b)15s c)30s d)60s e) none of the above
b)15s Note: divide to find answer 30/2=15
If a freely falling object were equipped with a speedometer on a planet where the acceleration due to gravity is 20 m/s^2,then it's speed reading would increase each second by___. a) 10m/s b)20m/s c)30m/s d)40m/s e) depends on it's initial speed
b)20m/s
A car traveling at 22m/s comes to an abrupt halt in 0.1 second wh en it hits a tree. What is the deceleration of the car? a) 110 m/s^2 b) 220 m/s^2 c) 800 m/s^2 d) 880 m/s^2 e) need more information
b)220 m/s^2 22*10=220 need to change 0.1 second into a whole number. Move decimal ove by 2.
The total time it takes a projectile fired straight up at 10m/s to reach the top of its path and return to its starting point is about___. a) 1s b) 2s c) 10 s b) 20s
b)2s
Phil stands at rest with both feet on a scale that reads 500N. When he gently lifts one foot, the scale reads___. a) less than 500N b)500N c) more than 500N
b)500N
A mobile phone is pulled northward by forc of 10N and at the same time pulled south ward by another force of 15N. The resultant force on the phone is___. a)0 N b)5N c)25N d)150N
b)5N
If an object moves with constant acceleration, its velocity must___. a)be constant also. b) change by the same amount each second. c) change by varying amounts depending on it's speed. d) always decrease.
b)change by the same amount each second.
A coin and a ring roll down an incline at the same time. The one to first reach the bottom is the___. a) ring b) coin c)both reach the bottom at the same time.
b)coin
A Earth's mass decreased to one-half it's original mass with no change in radius, then your weight would___. a) decrease to one- quarter b) decrease to half c) stay the same d) none of the above
b)decrease to half
Suzie skydriver jumps from a high- flying plane. As her velocity of fall increases, her acceleration___. a) increases b) decreases c) remain unchanged regardless of air resistance.
b)decreases
If vertically falling rain makes slanted 45 degree streaks on the side windows of a moving car, the speed of the car___. a) is less than the speed of the falling drops. b) equals the speed of the falling drops. c) exceeds the speed of the falling drops d) need more information
b)equals the speed of the falling drops. c^2=a^2+ b^2-a^2+a^2=b^2+b^2 c^2=2a^2=2b^2 ________________ |. / | | / | | / | | c /. | | /. | b | / | | / | | / )45 | -------------> a
A truck is moving at constant velocity. Inside the storage compartment, a rock is dropped from the midpoint of the ceiling and strikes the floor below. The rock hits the floor____. a) behind the midpoint of the ceiling. b) exactly below the midpoint of the ceiling c) ahead of the midpoint of the ceiling. d) what information is needed to solve this problem. e) none of these.
b)exactly below the midpoint of the ceiling.
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___. a) revolve in a smaller circle. b) follow a straight line path c)increase it's speed. d) continue to follow a circular path.
b)follow a straight line path.
As water drops fall at a steady rate from a leaking faucet they___. a) get closer together. b) get farther apart. c) remain at a relatively fixed distance from one another.
b)get farther apart.
The speedometer of an automobile reads___. a) average speed b) instantaneous speed c) accelerated speed
b)instantaneous speed
The distance a freely falling object falls from rest in one half second is ___. a) 2m b)4m c)6m b) none of the above
b)none of the above Note: Need to divide to find answer 10/2=5
a pair of action-reaction forces always___. a) act on the same object b) occur simultaneously c)comprise a pair of interactions d) all of the above e) none of the above
b)occur simultaneously
Which requires the most amount of work by the brakes of a car? a) slowing down from 70km/h to a stop b) slowing down from 100km/h to 70km/h c)equal amounts for either
b)slowing down from 100km/h to 70km/h
Which has greater kinetic t, a car traveling at 30km/hr or a car of half the mass traveling at 60km/hr? a) the 30 km/hr b) the 60 km/hr c) Both have the same kinetic energy d) more information is needed about the distance traveled
b)the 60 km/hr
For a system in mechanical equilibrium___. a) the resultant torque must be zero b) the resultant force and torques must both be zero c)the resultant force and torque must be equal d)the resultant force must be zero
b)the resultant force and torques must both be zero
A ball is thrown upwards and returns to the same location. Compared with it's initial speed it's speed when it returns is about___. a) half as much b) the same c) twice as much d) four times as much
b)the same
A bird flying at 8 km/h in a 6-km/h crosswind has a resultant speed of___. a) 6 km/h b)8 km/h c)10 km/h d)14 km/h
c) 10 km/h Note: v=√(8^2)+(6^2) v=√64+36 v=√100 v= 10
A jumbo plane has mass of 100,000 kg. The thrust for each of its four engines is 50,000 N. What is the jet's acceleration when taking off? a) 0.25 m/s^2 b) 1m/s^2 c) 2m/s^2 d)4m/s^2 e) none of the above
c) 2m/s^2 50,000*4=200,000 200,000/100,00=2
An automobile and a golf cart traveling at the same speed collide head-on. The impact force is___. a) greater on the bug b) greater on the golf cart c) The same for both
c) The same for both.
When a rocket forces exhaust gases downward, the exhaust gases___. a) as the name implies, soon exhaust their influence. b) play no further role in the motion of the rocket c) exert an upward force on the rocket.
c) exert an upward force on the rocket.
The player it's a ball with a bat. If action is the force we're good night against the ball, reaction is the___. a) air resistance on the ball b) weight of the ball c) force that the ball exerts on the ball d)grip of the player's hand against the ball. e) weight of the bat.
c) force that the ball exerts on the ball
If the polar icecaps melted, the resulting water would Spears over the entire Earth. This new mass distribution would tend to make the length of a day___. a) shorter at first, then longer. b) longer at first, then shorter c) longer d) stay the same e) shorter
c) longer
Phil Physiker standing at the edge of a cliff throws one ball striaght up and another ball straight down, both with the same speed. Neglecting air resistance, which ball hits the ground below with the greatest speed? a) the one thrown upward b) the one thrown downward c) neither, both hit with the same speed.
c) neither, both hit with the same speed.
The force of gravity acts on all apples on an apple tree. Some apples are twice as far from the ground as others. For the same mass these twice-as-high apples have___. a)1/4 the weight b)1/2 the weight c) practically the same weight.
c) practically the same weight.
A sheet of paper can be withdrawn from under a container of milk w/o toppling it if the paper is jerked quickly. This best demonstrates that ___. a) there is an action reaction pair of forces. b) gravity tends to hold the milk carton secure. c) The milk cartoon has inertia. d) the milk carton has no acceleration. e) none of these.
c) the milk carton has inertia
A bag of groceries that has a mass of 10 kilograms weighs about___. a)1N b)10N c)100N d)1000N e) greater than 1000N
c)100N Note: 1kg=10N
A 1 kg mass at the Earth's surface weights___. a) 1N b)5N c)10N d)12N e) none of the above
c)10N
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___. a) 6km/h b)8km/h c)10km/h d)20 km/h
c)10km/h Note: v=√(8^2)+(6^2) v=√64+36 v=√100 v= 10
A river a hundred mile wide flows one meter a second due south. Q boat that travels one meter a second relative to the water is point Ed due east as it crossed from the West bank. Relative to it's starting point, the boat travels___. a) nowhere b)100m c)141m d)200 m e) more than 200m
c)141m Note: time= distance/ average speed ( riverboat width 100 m) boat 1m/s -----------------> | \ |. \ about 1.4 | \ r I v e r 1 m/s
An object falls freely from rest on a planet where the acceleration due to gravity is twice as much as on Earth. In the first 5 seconds it falls a distance of___. a) 100m b)150m c)250m b)500m e) none of the above
c)250m Note: How to find the answer? (1/2)10×5^2=125 on Earth 125×2=250
When karate chop breaks a board with a 3000 N and blow, the amount of force that acts on the hand is___. a) zero b) 1500N c)3000N d)6000N
c)3000N
A 300-kg bear grasping a vertical tree slides down at constant velocity. The friction force between the tree and the bear is___. a) 30N b)300N c)3000N b) more than 3,000 N.
c)3000N Note: multiple 300×10
If a rocket initially at rest accelerates at a rate of 50 m/s^2 for one minute, it's speed will be___. a)50m/s b)500m/s c)3000m/s d)3600m/s
c)3000m/s Note: multiple to find answer 50*60=3000
A 1000 kg automobile enters a freeway on- ramp at 20 m/s and accelerations for a 50kg person? a) 500 N b) 2500N c)5000N d)25,000N e) none of the above
c)5000N 1kg=10 (50*10)(10)=5000
The famous Leaning Tower of Pis doesn't topple over because it's center of gravity is___. a) in the same place as it's center of mass b) stabilized by it's structure c) above a place of support d) displaced from it's center e) relatively low for such a tall building.
c)above a place of support
A baseball bat is balanced on a fulcrum. The center of gravity of the bat is located___. a) closer to the handgrip b) closer to the heavy end c) above the fulcrum
c)above the fulcrum a point where the lever rests/ supported
Whereas impulse involves the time that a force acts, work involves the___. a) time and distance that a force acts b) acceleration that a force produces c) distance that a force acts
c)distance that a force acts
Your pet hamster sits on a record player that has constant angular speed. If the hamster moves to a point twice as far from the center, then its linear speed___. a)1/2 b) remains the same c) doubles
c)doubles
The force with which Earth pulls on the Moon is___. a) somewhat greater than the moon's pull on Earth. b) the only force acting between Earth and moon. c) equal in magnitude to the force that moon pulls on Earth.
c)equal in magnitude to the force that moon pulls on Earth
A flywheel's diameter is twice that of another of the same shape and mass. Rotational inertia of the larger flywheel is___. a) two times the others b) the same as the others c) four times the others d) half the others
c)four times the others
An pair of you 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___. a) heavier car b) lighter car c) same on each
c)same on each
the winner in a tug-of-war exerts the greatest force on___. a) the opponent b) his or her end of the rope c) the ground
c)the ground
If you do work on an object in one-third the usual time, your power output is___. a)the usual power output b)one third the usual power output c) three times the usual power output d) impossible to predict without additional information.
c)three times the usual power output
A vehicle undergoes acceleration when it___. gains speed b)loses speed c) changes it's direction d)all of the above
d) all of the above
You experience weightlessness___. a) in the absence of a supporting surface b) momentarily when you step off a chair c) in a freely falling elevator d) all of the above
d) all of the above
The force exerted on the tires of a car that directly accelerate it along road is exerted by the___. a) engine b) tires c) air d) road e) none of the above
d) road
A moving body must undergo a change in___. a) position b) distance c) directions d) velocity
d) velocity
A car moves 4 times as fast as another identical car. Compared to the slower car, the faster car has ___. a)8 times the KE. b)12 times the KE c)4 times the KE d)16 times the KE
d)16 times the KE
If a power plant is 30% efficient, and the transmission system that delivers power to consumers is 60% efficient, then the overall efficient, then the overall efficiency is___. a)90% b)18% c)30% d)60% e) none of these
d)18%
Using 1000 J of work, a toy elevator is raised from the ground floor to the second floor in 20 s. How much power does the elevator use? a)20 W b)20,000W c)1000W d)50W c)100W
d)50W divide 1000÷20=50
A mosquito flying at 3m/s encounters a breeze blowing a 3 m/s in the same direction has a speed of ___. a) 0 m/s b) 3m/s c) 4 m/s d) 6 m/s
d)6m/s
A car's speed 3 seconds after accelerating from rest at 2 m/s2 is___. a)2 m/s b)3m/s c)4m/s d)6m/s
d)6m/s Note: multiple to find your answer 3*2=6
According to Newton's law inertia, a rail road train in motion should continue going forever even if it's engine is turn off. We never observe this because railroad trains ___. a) must go up and down hills. b) move too slowly. c) are much to heavy. d) always have forces that oppose their motion.
d)always have forces that oppose their motion.
A feather and a coin will have equal accelerations when falling in a vacuum because___. a) their velocities are the same. b) the force of gravity is the same for each in a vacuum. c) the force of gravity does not act in a vacuum d)the ratio of both the feather's and coin's weight to mass is the same. e) none of the above
d)the ratio of both the feather's and coin's weight to mass is the same.
You know that you can safely stand on the overhanging end of a heavy plank that rests on a table. How far out depends on your mass and the mass of the plank. Suppose you can stand on the end of a plank that overhangs the supporting table 1/4 it's total length. Then how massive is the plank compared to your mass? a) 1 1/2 your mass b) twice your mass c) 4 times your mass d) the same as your mass e)1/2 your mass
d)the same as your mass
A 1kg 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___. a) 1/2 N b)1N c)5 N d) 7.5N e)10N
e) 10N 1kg=10N
Half- way to the center of a completely hollow planet with a thin uniform shell, your weight would be___. a) one- quarter of your weight on the surface. b) one- half of your weight on the surface. c) three- quarter s of your weight on the surface. d) the same as at the surface. e) zero
e) zero Note: Hollow planet in 0
Suppose the circumference of a bicycle wheel is 2 meters. If it rotates at 1 revolution per second when you are riding the bicycle, then your speed will be___ . a)3 m/s b)3.14m/s c)1m/s d)6.28m/s e)2m/s
e)2m/s divide
A TV set is pushed a distance of 2 m with a force of 20 N. How much work is done on the set? a)2 J b)20J c)800J d) 10J e)40J
e)40J force x 2=20
A object at rest may also have___. a) momentum b) kinetic energy c) velocity d) speed e) potential energy
e)potential energy object at rest can't have speed, velocity, or acceleration.