Florida Science Grade 7

Chapter 5: Work and Simple Machines

Work and Simple Machines

1
A drill bit is an example of which type of machine?
A)screw
B)lever
C)pulley
D)wheel and axle
2
On what point does a lever pivot?
A)the fulcrum
B)the arm
C)the middle
D)the end
3
What is a sign that work is being done?
A)density
B)matter
C)motion
D)mass
4
What happens to the amount of power expended when you are climbing stairs and then climb faster?
A)It increases.
B)It stays the same.
C)It stops.
D)It decreases.
5
A ramp in a building is an example of which machine?
A)wedge
B)lever
C)inclined plane
D)pulley
6
Name the four simple machines.
A)inclined plane, lever, wheel and axle, and pulley
B)wedge, lever, pulley, and wheel
C)plane, lever, screw, and wedge
D)screw, lever, wedge, and plane
7
What does a screw consist of?
A)a wheel and axle in a vertical position
B)an inclined plane wrapped around a cylinder
C)a wedge wrapped around a pipe
D)a lever wrapped around a pole
8
What is the mechanical advantage if 50 J are put in and 200 J are produced?
A)4
B)1000
C)50
D)200
9
Using an inclined plane allows you to apply __________.
A)no force
B)the same force
C)a lesser force
D)a greater force
10
When you climb stairs and then walk down a hallway, in which direction is the work done?
A)downward
B)upward
C)along the hallway
D)in the opposite direction that you walk
11
Which of the following do you think a wheel and axle is most closely related to?
A)lever
B)wedge
C)pulley
D)inclined plane
12
The efficiency of all machines is __________.
A)more than 100 percent
B)exactly 100 percent
C)impossible to calculate
D)less than 100 percent
13
Using several pulleys together is known as a __________.
A)pulley system
B)machine system
C)wheel and axle
D)pulley group
14
What happens to the total amount of work done when you use a machine compared to not using a machine?
A)It stays the same.
B)It goes to zero.
C)It decreases.
D)It increases.
15
Which simple machines are found on a hammer?
A)wedge and plane
B)lever only
C)plane and lever
D)screw and pulley
16
Which is an example of work being done in a scientific sense?
A)carrying a box
B)pushing against a stationary box
C)lifting a box
D)doing homework
17
A 5,000 N block was lifted 10 m. How much work was done?
A)50,000 J
B)500 J
C)5,000 J
D)50 J
18
A chisel is an example of which machine?
A)wheel and axle
B)wedge
C)lever
D)pulley
19
What is the scientific formula for work?
A)W = F x d
B)W = F + d
C)W = F - d
D)W = F/d
20
The unit for work is a joule, which is equal to __________.
A)N/m
B)N - m
C)N + m
D)N x m
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