Chapter 5:
Machines
Practice Test
1.
What is the term used for the force applied to a machine?
a.
applied force
b.
resistance force
c.
machine force
d.
effort force
Hint
2.
What is the science of making machines suitable for the people who use them?
a.
ergonomics
b.
biotechnology
c.
economics
d.
tectonics
Hint
3.
How are work, power, and time related?
a.
Time is power over work.
b.
Work is time over power.
c.
Power is work over time.
d.
Work is power over time.
Hint
4.
How does increasing the number of threads on a screw change the mechanical advantage of a screw?
a.
It is impossible to calculate the mechanical advantage of a screw.
b.
The mechanical advantage of the screw is unaffected.
c.
The mechanical advantage of the screw decreases.
d.
The mechanical advantage of the screw increases.
Hint
5.
Suppose you need to place a 5-kg block of ice onto the shelf of a freezer 2.0 m high. The ice will soon start melting, so you must place the ice in the freezer in 10 s. How much power will you need?
a.
10 W
b.
25 W
c.
2.5 W
d.
1 W
Hint
6.
What is the basic principle of using a lever?
a.
You exert a small force over a long distance.
b.
The amount of work the lever performs is more than the work you perform.
c.
The resistance force is greater than the effort force.
d.
All of the above are correct.
Hint
7.
What is the basic advantage of single fixed pulley?
a.
The pulley changes the distance over which the effort force is applied.
b.
The pulley changes the direction of the effort force.
c.
The force exerted is reduced compared to the resistance force.
d.
The pulley decreases the amount of work needed to move an object.
Hint
8.
What does the mechanical advantage of a machine tell you?
a.
how useful a machine may be
b.
how much bigger resistance force is compared to effort force
c.
The force exerted is reduced compared to the resistance force.
d.
All of the above are correct.
Hint
9.
What is the mechanical advantage of a lever if the effort arm is 2.0 m long and the resistance arm is 0.5 m long?
a.
1[.0]
b.
4[.0]
c.
0.25
d.
impossible to calculate with the information provided
Hint
10.
Which of the following is an example of a compound machine?
a.
a doorknob
b.
a can opener
c.
a screwdriver
d.
an axe
Hint
11.
When using a wheel and axle, what happens as the size of the wheel increases?
a.
The distance the axle moves as you turn the wheel increases.
b.
The amount of work you must do is less.
c.
You need less effort force to turn the axle.
d.
You need more effort force to turn the axle.
Hint
12.
How can you increase the efficiency of a machine?
a.
by reducing losses due to friction
b.
The amount of work you must do is less.
c.
You need less effort force to turn the axle.
d.
All of the above.
Hint
13.
A screw and a wedge are both similar to what other kind of simple machine?
a.
an inclined plane
b.
a wheel and axle
c.
a lever
d.
a pulley
Hint
14.
Suppose you must lift a 100-kg box to a table 1 m high. How does the use of an inclined plane affect the amount of work you must perform to lift the box?
a.
An inclined plane increases the amount of work you must perform.
b.
An inclined plane does not change the amount of work you must perform.
c.
You can perform less work with a longer inclined plane.
d.
You can perform less work with a shorter incline plane.
Hint
15.
What is the mechanical advantage of a lever if the effort force is 2 N and the resistance force is 8 N?
a.
5
b.
16
c.
4
d.
2
Hint
