Chapter 7 Review Test

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Name:

Chapter 7 Review Test

True/False

Indicate whether the sentence or statement is true or false.

When a machine is used to do work, the force applied by the machine is called the effort force.

Under certain conditions, it is possible to get more work out of a machine than you put into it.

Some machines don't multiply the force that is applied to them.

Examples of all three classes of levers are found in the human body.

Bionics is the science that deals with the study of compound machines.

Modified True/False

Indicate whether the sentence or statement is true or false. If false, change the identified word or phrase to make the sentence or statement true.

The science of designing artificial parts for the human body is called robotics. _______________

The longer arm of a lever with a mechanical advantage greater than 1 is the effort arm. _______________

Friction changes the useful work of a machine into mechanical energy. _______________

Reducing friction increases the ideal mechanical advantage of a machine. _______________

Multiple Choice

Identify the letter of the choice that best completes the statement or answers the question.

Figure 7-2A shows a block being moved up an inclined plane. Figure 7-2B shows the same block being lifted the same distance by a fixed pulley. (Ignore friction.)

10.

The fixed pulley shown in Figure 7-2B does which one of the following?

a.	doubles the force required to lift the block
b.	decreases the force required to lift the block
c.	makes the block easier to lift by changing the direction of the force needed to lift it
d.	decreases the force required and changes the direction of the force required

11.

A slanted surface used to raise an object is _____.

a.	an efficiency board
b.	an effort ramp
c.	an inclined plane
d.	a screw
e.	a wedge

12.

A device that does work with only one movement and changes the size or direction of a force is _____.

a.	a compound machine
b.	an effort machine
c.	a screw
d.	a simple machine
e.	a wedge

13.

A bar that is free to pivot about a fixed point is a _____.

a.	fulcrum
b.	lever
c.	ramp
d.	screw
e.	wedge

14.

The rate at which work is done is called _____.

a.	efficiency
b.	effort time
c.	force
d.	power
e.	resistance time

15.

The work output of a machine divided by the work input is the _____ of the machine.

a.	efficiency	c.	power
b.	effort	d.	resistance

16.

The amount by which a machine multiplies an effort force is called the _____.

a.	efficiency factor	c.	mechanical advantage
b.	fulcrum	d.	resistance force

17.

An inclined plane with one or two sloping sides forms a machine called a _____.

a.	pulley
b.	lever
c.	ramp
d.	screw
e.	wedge

18.

An inclined plane wrapped around a cylinder post is a _____.

a.	block and tackle
b.	lever
c.	ramp
d.	screw
e.	wedge

19.

A machine that changes only the direction of a force has a mechanical advantage of _____.

a.	100
b.	10
c.	5
d.	2
e.	1

20.

A winding mountain road is an example of _____.

a.	a block and tackle
b.	a lever
c.	an inclined plane
d.	a wheel and axle
e.	a wedge

21.

When two or more simple machines work together, they are called _____.

a.	a compound machine
b.	an effort machine
c.	a screw
d.	a simple machine
e.	a wedge

22.

The unit of power is the _____.

a.	joule
b.	MA
c.	m/s
d.	second
e.	watt

23.

A lever with a mechanical advantage greater than 1 is used to _____.

a.	change direction
b.	increase distance
c.	increase force
d.	increase force and change direction
e.	decrease force

24.

Three of the following simple machines are basically the same. The one that does NOT belong with the group is the _____.

a.	lever	c.	wedge
b.	pulley	d.	wheel and axle

25.

An arrangement of pulleys designed to reduce the effort force is called a _____.

a.	block and tackle
b.	fixed pulley
c.	movable pulley
d.	simple pulley
e.	screw

26.

Two simple machines that are part of a bicycle are _____.

a.	a gear and a wheel and axle
b.	an inclined plane and a lever
c.	an inclined plane and a wedge
d.	a screw and an inclined plane
e.	a wheel and axle and an inclined plane

Matching

Match each item with the correct statement below.

a.	effort force	e.	simple machine
b.	compound machine	f.	resistance force
c.	prosthesis	g.	efficiency
d.	mechanical advantage

27.

artificial replacement part

28.

ratio of resistance force to effort force

29.

device that does work with only one movement

30.

the force you apply to a simple machine

31.

device made up of more than one simple machine

Problem

32.

Find the ideal mechanical advantage of the second-class lever shown in Figure 7-1.

33.

What would be the ideal mechanical advantage of the lever in Figure 7-1 if the fulcrum were moved 2 m to the right?

Figure 7-2A shows a block being moved up an inclined plane. Figure 7-2B shows the same block being lifted the same distance by a fixed pulley. (Ignore friction.)

34.

In Figure 7-2A, what is the ideal mechanical advantage of the inclined plane?

35.

In Figure 7-2A, what is the weight of the block?

36.

In Figure 7-2A, what is the amount of work required to move the block along the total length of the inclined plane?

37.

If the weight of the block in Figure 7-2A were doubled, how much work would be required to move the block along the total length of the inclined plane?

38.

If the efficiency of the fixed pulley in Figure 7-2B were 100%, how much force would be required in using the pulley to lift the block off the ground?

39.

Calculate the ideal mechanical advantage of a lever that is 6-m long and that has a 4.5-m effort arm.

40.

A 24-cm long screwdriver is used as a lever to open a paint can. If the fulcrum is 0.5 cm away from the end of the screwdriver, what is the screwdriver's ideal mechanical advantage?