Physical Science Final Exam Part 2

Which has greater kinetic energy, a car traveling at 30 km/h or another car of half the mass traveling at 60 km/h?

60-km/h car

A boxer punches a sheet of paper in midair from rest to a speed of 40 m/s in 0.05 s. If the mass of the paper is 0.01 kg, the force of the punch on the paper is

8 N

A 2-kg mass weighs 20 N and is held 4 m above the ground. Its potential energy relative to the ground is

80 J

Two objects move toward each other due to gravity. As the objects get closer and closer, the force between them

increases

When the distance between two stars decreases by half, the force between them

increases four times as much

A projectile is fired horizontally. With no air resistance it maintains its horizontal component of velocity because

no horizontal forces act on it

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

not enough information

A moving object has

speed, momentum, energy, and velocity

Newton discovered

that gravity is universal

A hunter aims a rifle at an angle of 10° below the horizontal. The hunter fires a bullet while simultaneously dropping another bullet from the side of the rifle. Which bullet hits the ground first?

the fired one

Consider driving into a massive concrete wall with no "give," versus having a head-on collision at the same speed with an identical car moving toward you at the same speed. It would be more damaging to hit the

the same

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

0.5 m/s

A ball is moving at 4 m/s and has a momentum of 48 kg∙m/s. What is the ball's mass?

12 kg

A car moves 4 times as fast as another identical car. Compared with the slower car, the faster car has

16 times the kinetic energy

Exert 100 J in 50 s and your power output is

2 W

A bow is drawn so that it has 40 J of potential energy. When the arrow is fired its kinetic energy is ideally

40 J

A projectile is thrown into the air at an angle of 50° and lands on a target that is at the same level the projectile started. With no air resistance it will also land on the target if it is thrown at an angle of

40 degrees

A stone is thrown horizontally from the top of a cliff. One second after leaving your hand it drops a vertical distance of

5 m

In raising a 5000-N piano with a pulley system, for every 1 m of rope pulled down, the piano rises 0.1 m. Ideally, this means the force needed to lift the piano is

500 N

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?

6 m/s

A clerk can lift containers a vertical distance of 1 m, or roll them up a 2-m-long ramp to the same elevation. With the ramp, the applied force needed is

Half as much

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

a bullet fired from a rifle begins to fall

as soon as it leaves the barrel

You're driving down the highway and a lovebug spatters onto your windshield. Which undergoes the greater change in momentum?

both are the same

Which requires more work: lifting a 50-kg sack vertically 2 m or lifting a 25-kg sack vertically 4 m?

both require the same amount of work

When the distance between two stars doubles, the force between them

decreases by one quarter

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

distance that a force acts

If your mass remained the same while the mass of Earth doubled while staying the same size, your weight would

double

An Earth satellite is an elliptical orbit. It travels slowest when it is

farthest from Earth

A heavy truck and a small car rolling down a hill at the same speed are forced to stop in the same amount of time. Compared with the force to stop the car, the force needed to stop the truck is

greater

When a non-hybrid car brakes to a stop its kinetic energy transforms to

heat

The speed of a bullet fired from a gun will be about the same as the speed of the recoiling gun

if the masses of the bullet and gun are equal

A cannonball fired from a long-barrel cannon will have a greater muzzle velocity because the cannonball receives a greater

impulse

An Earth satellite is in an elliptical orbit. The satellite travels fastest when it is

nearest earth

According to the impulse—momentum equation Ft = change in mv, a bungee jumper in fall has momentum which is reduced by the force F exerted by the bungee cord. If m is the mass of the jumper, then v in the equation is the speed of the

jumper

According to Newton, the greater the distance between gravitationally interacting objects, the

less the gravitational force between them

When you are in the way of a fast-moving object and can't get escape, you will suffer a smaller force if the collision time is

long

An object is thrown vertically into the air. Because of air resistance, the time for its descent will be

longer than the ascent time

When a cannon fires a cannonball at a given speed, the smaller recoil speed of the cannon is due to different

masses

A golf ball is thrown at and bounces backward from a massive bowling ball that is initially at rest. After the collision, compared to the golf ball, the bowling ball has more

momentum, but less kinetic energy

A car traveling along the highway needs a certain amount of braking force to stop. More braking force is required when the car has

more momentum, more mass, and less stopping distance

A 1-kg ball dropped from a height of 2 m rebounds only 1.5 m after hitting the ground. The amount of energy converted to heat is about

more than 2.0 J

An object that has kinetic energy must be

moving

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

An object lifted 10 m gains a certain amount of potential energy. If it is lifted 20 m, its gain in potential energy is

twice as much

A 1000-kg car and a 2000-kg car are hoisted the same distance in a service station. Raising the more massive car requires

twice as much work

If you push an object twice as far while applying the same force, you do

twice as much work

Inside a freely falling elevator your

weight is zero

Passengers in a high-flying jumbo jet feel their normal weight in flight. Passengers in an orbiting space vehicle do not because passengers are

without stopping forces