Download Ch 7 Book reading homework

Chapter 7: Work and Energy
Section 7.1 Pages 147-154
1.
E
is responsible for all C
2. Energy is what makes the universe
A
that occur in the physical world.
.
3. The more energy you have the B
W
you can do.
the changes can be, and the more
4. True or False: If there is zero energy zero changes can be made.
5. How did ancient people move huge stones to build monuments, such as the Great Pyramid of Giza,
long before the invention of trucks and engines?
6. Define MACHINE:
7. Define INPUT:
8. Define OUTPUT:
9. Draw a diagram in the box to the right that shows
something you might use on a daily basis other than a bike.
Show the INPUT and OUTPUT in the diagram.
10. Define SIMPLE MACHINE:
11. True or False: A simple machine can accomplish a task with six movements.
12. Fill in the table below.
Simple
Machine
Wedge
Definition or your own
description of it.
Two inclined planes put
together.
Describe what you could
use it for in your life.
Drawing
Cutting wood
Gears
Lever
Wheel & Axel
Rope & Pulley
Ramp
13. Define MECHANICAL ADVANTAGE:
Mechanical Advantage
14. If the If the mechanical advantage is LARGER THAN ONE, the output
force is
than the input force. A mechanical advantage
SMALLER THAN ONE means the output force is
than the input force.
15. Write the formula for MECHANICAL ADVANTAGE in the box to the
right.
I’m a nut
cracker!
16. Draw an arrow in each of the four pictures to the right showing
where the FULCRUM is.
17. True or False: By changing the position of the fulcrum, you can alter
the amount of input force needed to produce the desired output.
18. If the input arm of a lever is 5 times longer than the output arm
then the output force is
times the input force.
19. Fill in the table about the three classes of levers.
Class of Lever
Fulcrum Placement
Two Examples
20. Define WORK:
21. The unit for WORK is
22. The unit for ENERGY is
23. 1 Nm =
24. True or False: In Physics, if a large force is applied to an object yet the
object doesn’t move WORK has still been done.
Work
25. True or False: A force applied in the opposite direction of movement is
doing WORK.
26. Write the formula for WORK in the box to the right.
27. How much work is done by a person who pushes a cart with a force of 70 N if the cart moves 2 meters
in the direction of the force?
28. How far does a 1000 N force have to move to do 5000 joules of work? (Hint: You may need to look
back at the variations of the Work formula. Make it so DISTANCE is by itself in the equation)
29. As shown in the picture to the right, a crane does 4000 joules of work
lifting a piano up to a third floor apartment. The apartment is 40 meters
up. How much force does the crane use? (Hint: You may need to look
back at the variations of the Work formula. Make it so Force is by itself
in the equation)
Section 7.2 Pages 155-166
30. True or False: In Physics there is only one form of energy.
31. Define ENERGY:
32. List three types of changes that energy can make.



33. How can the energy in gasoline be used?
34. How can the energy in a piece of wood be used?
35. Define Joule:
36. How many joules of energy are used by a 100-watt light bulb every second?
37. Describe how energy is nature’s money.
38. Define MECHANICAL ENERGY:
 Give an example of mechanical energy.
39. Define CHEMICAL ENERGY:
 Give an example of chemical energy.
40. Where does ELECTRICAL ENERGY come from?
 Give an example of electrical energy.
41. PRESSURE ENERGY is found in
G
 Give an example of pressure energy.
and
L
42. Define ELASTIC ENERGY:
 Give an example of elastic energy.
43. Define NUCLEAR ENERGY:
 Give an example of nuclear energy.
44. Define RADIANT ENERGY:
 Give an example of radiant energy.
45. List three ways in which you may use the ELECTROMAGNETIC SPECTRUM in your life



46. Living things and human technology derive virtually all of their energy from the
.
47. True or False: If a rock is lifted against gravity it has stored energy.
48. True or False: A rubber band can have stored energy.
49. True or False: It is impossible in Physics to do Work without any Energy.
50. Define POTENTIAL ENERGY:

Give an example of something that has potential energy.
51. Write the formula for POTENTIAL ENERGY in the box to the right.
52. Calculate the potential energy of a 4 kilogram cat crouched 3 meters off
the ground.(Hint: remember gravity on Earth is 9.8 m/s2)
Potential Energy
53. Define KINETIC ENERGY:
Kinetic Energy
54. Write the formula for KINETIC ENERGY in the box to the right.
55. Calculate the kinetic energy of a 4 kilogram cat running at 5 meters per
second.
56. True or False: Energy can change from one type of energy to another.
57. Place the letter of each of the following statements where they belong on the
picture to the right.
A. The skier is at maximum Potential Energy
B. The skier is at minimum Potential Energy
C. The skier is at maximum Kinetic Energy
D. The skier is at minimum Kinetic Energy
E. The skier has both Potential Energy and Kinetic Energy.
58. Define LAW OF CONSERVATION OF ENERGY:
59. Place the letter of each of the following statements where they belong
on the picture to the right. (Hint: The spots you pick don’t have to be on an
image of the ball in flight)
A. All potential energy
B. Two places where it is half potential and half kinetic energy
C. Two places where it is mostly Kinetic Energy
60. True or False: If gravity is the only force acting on a ball thrown in the air, it should return to your hand
with exactly the same speed and kinetic energy it started with.
61. If energy can never be created or destroyed why is it so important to conserve energy in our everyday
lives?
62. Explain why Electric Power Plants don’t make energy.
63. Some, but not all, of the gasoline used by a car’s engine is transformed into kinetic energy. Where else
might some of the energy go in this system?
Section 7.3 Pages 167-171
64. Define WORK INPUT:
65. Define WORK OUTPUT:
66. The energy output of a process or machine can N
E
67. Define EFFICIENCY:
68. Write a formula for EFFICIENCY in the box to the right. There isn’t an obvious
one in the chapter. (Hint: You will have to figure it out and write it the way it
should be written as a formula.)
the energy input.
Efficiency
69. A car transforms gasoline into energy for the car to move. What percent of the energy in a gallon of gas is
actually transformed into output work?
What percent of the gasoline is wasted as heat?
70. What is the average efficiency of the Earth’s absorption of the Sun’s energy?
71. Draw a picture in the box below showing what happens to the incoming solar radiation here on Earth. Be sure to
show what percentage of the Sun’s energy ends up in each area.
Incoming Solar Radiation to Earth
72. What do scientists believe will happen if the Earth’s absorption of the Sun’s energy efficiency were to drop by a
few percentage points?

What is one way that this decrease could occur?
73. What do scientists believe will happen if the Earth’s absorption of the Sun’s energy efficiency were to increase
by a few percentage points?

What is one way that this increase could occur?
74. Power describes how fast energy is T
to an object.
Power
75. Define POWER:
76. Write the formula for POWER in the box to the right.
77. Define WATT:
78. Define HORSEPOWER:
79. Which of the following would produce 200 watts of power?
a. 100 J of work done in 2 s
c. 2,000 J of work done in 5 s
b. 400 J of work done in 2 s
d. 2 J of work done in 100 s
80. A 100 Newton object is lifted 100 meters in 100 seconds. What is the power generated in this situation?
(HINT: You will need to use the formula for WORK first and then use the formula for POWER)
Use this to study from on your chapter 7 quiz. Glue this in your notebook