Name ______________________________________ Date ____________ Class ______________________
Conceptual Physics • CHAPTER 8
HOMEWORK 8-3
1.
What does it mean to say that in any system the total energy score stays the same?
2.
In what sense is energy from coal actually solar energy?
3.
How does the amount of work done on an automobile by its engine relate to the energy
content of the gasoline?
4.
In what two ways can a machine alter an input force?
5.
In what way is a machine subject to the law of energy conservation? Is it possible for a machine
to multiply energy or work input?
6.
What does it mean to say that a machine has a certain mechanical advantage?
7.
In which type of lever is the output force smaller than the input force?
8.
What is the efficiency of a machine that requires 100 J of input energy to do 35 J of useful
work?
Name ______________________________________ Date ____________ Class ______________________
Conceptual Physics • CHAPTER 8
HOMEWORK 8-3
9.
What is the difference between theoretical mechanical advantage (IMA) and actual mechanical
advantage (AMA)? How would these compare if the machines were 100% efficient?
10. What is the efficiency of her body when a cyclist expends 1000W of power to deliver
mechanical energy to the bicycle at the rate of 100 W?