Physics 101 Burton Final Example Exam

. Two identical gliders slide toward each other on an air track. One moves at 1 m/s and the other at 2 m/s. They collide and stick. The combined mass moves at

1/2 m/s

Do 100 J of work in 50 s and your power output is

2 W

What impulse is needed to stop a 1200-kg car traveling at 20 m/s?

24,000 N.s

A car with a mass of 2000 kg moves at 10 m / s. Calculate the braking force needed to bring the car to a halt in 5 seconds.

4000 Newtons

A 5-kg fish swimming at a speed of 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 1-kg object rests on a table 1 m above the floor. What is the gravitational potential energy in Joules of the object with respect to the floor?

9.8

The car moving at 50 kilometers/hour skids 10 meters with locked brakes. How far will the car skid with locked brakes if it is traveling at 150 kilometers/hour?

90 meters

Which of the following is true about momentum? (a) it is a vector (b) it is a product of mass times velocity (c) impulses are required to change it (d) all of the above (e) none of the above

All of the above

A force times time is most appropriately called

An impulse

When you jump from an elevated position you usually bend your knees upon reaching the ground. By doing this, you make the time of the impact about 10 times as great as for a stiff-legged landing. In this way the average force your body experiences is

about 1/10 as great

Inside a freely-falling elevator, there would be no

apparent weight for you

At what point in its motion is the kinetic energy of a pendulum bob a minimum?

at the highest points in motion

A merchant of gold should_________ at a high altitude and ___________ at a low altitude.

buy, sell

A coin and a ring roll down an incline starting at the same time from rest. The one to reach the bottom first will be the

coin

When a spinning ice skater draws her arms in close to her body, she starts to spin faster. This is an example of

conservation of angular momentum

A car travels in a circle with constant speed. The net force on the car is

directed towards the center of the curve

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

distance that a force acts

When a car is braked to a stop, its kinetic energy is transformed to

heat energy

Padded dashboards in cars are safer in an accident than nonpadded ones because an occupant hitting the dash has

increased time of impact and decreased impact force

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

increases four times as much

The planet Jupiter is about 300 times as massive as earth, yet on its surface you would weight only about 3 times as much. This is because

jupiters radius is 10 times the earths radius

When you are in the way of a fast-moving object and can't get out of its way, you will suffer a smaller force of impact if you decrease its momentum over a

long time

A moving object on which no forces are acting will continue to move with constant

momentum

The reason the moon does not crash into the earth is that the

moon has a sufficient tangential speed

An object that has kinetic energy must be

moving

Which is the larger force?(a) the force that the earth exerts on the moon (b) the force that the moon exerts on the earth (c) neither

neither

Can a body have kinetic energy without having momentum?

no

If you push on an immovable wall for an hour, is there any work done on the wall?

no

A torque acting on an object tends to produce

rotation

Which is most responsible for the ocean tides?

the moon

If you push an object with twice the work input for twice the time, your power input is

the same amount as for half the work in half the time

The center of mass of a body can be outside of the body

true

Put a pipe over the end of a wrench when trying to turn a stubborn nut on a bolt, to effectively make the wrench handle twice as long, you'll multiply the torque by

two