Unit 5 Extra
Either print this page and complete or
(better yet) neatly show your answers on a separate page of paper.
All answers must be expressed as complete sentences and/or all work
shown to receive credit.
- Why does an automobile moving at constant velocity have to
keep burning fuel to maintain motion?
- The potential energy acquired in driving to the top of a
mountain is the same whether the road goes straight up or zigzags
in gradual slopes. Why then do most mountain roads wind up
gradually rather than rising straight up with a steep slope?
- A light truck and a heavy truck are traveling the same speed.
It is easier for the light truck to stop. Explain why.
- A light truck and a heavy truck are moving with the same
momentum. Which requires the most work to stop? Explain.
- When a rifle with a long barrel is fired, the force of
expanding gases acts on the bullet for a longer distance. What
effect does this have on the velocity of the emerging bullet?
- Explain why long range cannons have long barrels.
- A flight attendant and a passenger toss a ball back and forth
in a moving airplane. Does the kinetic 9. At what point in its
motion is the kinetic energy of a pendulum bob at a maximum?
______ At what point is its potential energy at a maximum?
________ When its kinetic energy is half its maximum value, how
much potential energy does it have?
- A physics instructor
demonstrates energy conservation by releasing a heavy pendulum bob
and allowing it to swing to and fro. What would happen if in her
exuberance, she gave the bob a slight shove as it left her nose?
- In the absence of air resistance, a ball thrown vertically
upward with a certain initial kinetic energy will return to its
original level with the same kinetic energy. When air resistance
is a factor affecting the ball, will it return to its original
height with the same, less, or more kinetic energy? Does this
answer contradict the conservation of energy principle? Explain.
- A child on a rooftop throws two identical balls with the same
initial speed in opposite directions - up and down. When the two
balls strike the ground, which ball is traveling with the greater
speed? Explain. (Be careful.)
- Discuss the design of a roller coaster in terms of
conservation of energy.
- Two classmates are discussing the design of a roller coaster.
One classmate says that each summit must be lower than the
previous one. The other classmate says that this is nonsense, for
as long as the first one is the highest it doesn't matter what
height of the others are. What would you say?
- You tell your friend
that no machine can possibly put out more energy than is put into
it. Your friend states that a nuclear reactor puts out more energy
than is put into it. What do you say?
- A ball dropped into a
steel plate loses 10 percent of its kinetic energy with each
bounce. Estimate the number of bounces the ball will make before
it fails to rise to half its initial height.
Resources for physics students are available through
links on the
Physics Home Page. Such resources include the
Physics Studios (a collection of animations and movies which
illustrate key physics concepts) and
Physics Classroom (an online tutorial written in an
This page created by Suzanne
South High School.
Comments and suggestions can be
sent by e-mail to
This page last updated on