Science Ch 3 Quiz

When you ride your scooter you have momentum. When you ride twice as fast you have A) almost twice the momentum. B) twice the momentum. C) four times the momentum. D) none of the above

B) twice the momentum.

When a boxer is moving away from a punch, the force experienced is reduced because A) momentum transfer is reduced. B) the time of contact is increased. C) the force is less effective. D) all of the above

B. the time of contact increased

Which has the greater kinetic energy A) a car traveling at 30 km/h B) a car of half the mass traveling at 60 km/h C) both the same D) need more information

a car of half the mass traveling at 60km/h

What is the speed of a 4-kg ball with a momentum of 12 kg∙m/s? A) 3 m/s B) 4 m/s C) 12 m/s D) 48 m/s

a. 3m/s

Two identical freight cars roll without friction towards each other on a level track. One car rolls at 2 m/s and the other car rolls at 1 m/s. After the cars collide, they couple and roll together with a speed of A) 0.5 m/s. B) 0.33 m/s. C) 0.67 m/s. D) 1.0 m/s.

a. 5m/s

Padded dashboards in cars are safer in an accident than non-padded ones because a person hitting the dash has A) increased time of contact. B) decreased contact force. C) both of these

c. both of these

Which requires more work: lifting a 50-kg sack vertically 2 m or lifting a 25-kg sack vertically 4 m A) lifting the 50-kg sack B) lifting the 25-kg sack C) both require the same amount of work

c. both require the same amount of work

Whether a truck comes to a stop by crashing into a haystack or a brick wall, the impulse is A) greater with the haystack. B) greater with the brick wall. C) both the same

c. both the same

which has the greatest momentum when moving- A) a container ship B) a bullet C) either of these depending on speed

c. either of these depending on speed

A cannonball fired from a long-barrel cannon will have a greater muzzle velocity because the cannonball receives a greater A) force. B) impulse. C) both of these D) none of the above

impulse

Consider a gun with a pellet that is more massive than the gun. The firing speed is greater for the

recoiling gun

The conservation of momentum is most closely related to Newton's

third law

You do work on a cart loaded with groceries. If you do this work in one-third the usual time, you expend A) one third as much power. B) the usual power. C) three times the usual power. D) need more information.

three times the usual power

The power expended for a barbell raised 2.0 m in 2 s is

1 W

What is the mass of a ball moving at 3 m/s with a momentum of 48 kg∙m/s? A) 4 kg B) 12 kg C) 16 kg D) 144 kg

16 kg

A shopping cart moves with a kinetic energy of 40 J. If it moves at twice the speed, its kinetic energy is

160 J

If you exert 6 N across a distance of 2 m in 3 s you'll deliver a power of

4 W

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

50 W

A 5000-kg freight car crashes into a 10,000-kg freight car at rest. They couple upon collision and move with a speed of 2 m/s. What was the initial speed of the 5000-kg freight car?* 0/1 A) 4 m/s B) 5 m/s C) 6 m/s D) 8 m/s

6 m/s

The impulse-momentum relationship is a direct result of

Newtons Second Law

If a monkey floating in outer space throws his hat away, the hat and the monkey will both move A) away from each other, but at different speeds. B) away from each other at the same speed. C) a short distance and then slow down. D) a short distance and then gain speed

a. away from each other, but at different speeds

When you jump from an elevated position you usually bend your knees upon reaching the ground. By doing this, the contact time is about 10 times more than for a stiff-legged landing and the average force your body experiences is reduced by

about 10 times

The force of a falling apple hitting the ground depends upon A) the speed of the apple just before it hits the ground. B) the time of contact with the ground. C) whether or not the apple bounces. D) all of the above

all of above

An astronaut floating alone in outer space throws a baseball. If the ball moves away at 20 m/s, the astronaut will move in the opposite direction at A) 20 m/s. B) a lower speed. C) a higher speed. D) more information needed

b. a lower speed

Which of the following has the largest momentum relative to Earth- A) a tightrope walker crossing Niagara Falls B) a pickup truck speeding along a highway C) a Mack truck parked in a lot

b. a pickup truck speeding along a highway

It is correct to say that impulse is equal to A) momentum. B) the change in momentum. C) the force multiplied by the distance the force acts. D) all of the above

b. change in momentum

When Jean standing on slippery ice catches her leaping dog Daisy, the momentum of both Jean and Daisy after the catch is A) greater than their combined momentum before the catch. B) equal to their combined momentum before the catch. C) somewhat less than their combined momentum before the catch.

b. equal to their combined momentum before the catch

A straw is used for a pea shooter. When you blow through the straw the speed of the emerging pea will be greater if the straw is A) cut in half. B) full length. C) either cut in half or full length.

b. full length

Work is done by gravity on a bowling ball that rolls A) along a horizontal surface. B) on a sloped surface. C) both of these D) none of the above

b. on a sloped surface

Which has greater kinetic energy: a car traveling at 30 km/h or another car of half the mass traveling at 60 km/h A) The 30-km/h car B) The 60-km/h car C) both have the same kinetic energy

b. the 60km/h car

An object lifted 10 m gains a certain amount of potential energy. If it is lifted 20 m, its gain in potential energy is A) less. B) the same. C) twice as much. D) four times as much.

c. twice as much

A 2-kg mass weighs 20 N and is held 4 m above the ground. Its potential energy relative to the ground is A) 8 J. B) 20 J. C) 60 J. D) 80 J.

d. 80J

The amount of potential energy possessed by an elevated object is A) relative to a chosen reference level. B) equal to the work done in lifting it. C) equal to the kinetic energy it will acquire when freely falling to its reference level. D) all of the above

d. all of the above

The massive ram of a pile driver falling from rest strikes a pile with a speed that depends on the A) initial height of the ram. B) initial potential energy of the ram. C) distance the ram falls. D) all of the above

d. all of the above

The change in momentum of an object is equal to the A) force acting on it. B) change in its velocity. C) object's mass times force acting on it. D) impulse that acts on it.

d. impulse that acts on it

Whereas impulse involves the time that a force acts, work involves the

distance that a force acts

When a bus brakes to a stop its kinetic energy transforms to

heat

An object may have potential energy because of its

location

When a cannon fires a cannonball at a given speed, the smaller recoil speed of the cannon is due to differences in A) forces. B) times. C) masses. D) momenta.

masses

An iron ball and wooden ball of the same size are dropped simultaneously from a tower and reach the ground at the same time. The iron ball has a greater

momentum

An object in motion is an object that has

momentum

A cat and a mouse run along a road with the same kinetic energy. The faster runner is the A) cat. B) mouse. C) both run at the same speed D) not enough information

mouse

The distinction between impulse and force involves the

time the force acts

If you do work on an object in half the time, your power output is

twice

Power is defined as the

work done on an object divided by the time taken to do the work