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online wst2 9thC

Multiple Choice
Identify the choice that best completes the statement or answers the question.

1.

What is a device that makes work easier by changing the size or direction of force?
 a. power c. machine b. watt d. force

2.

What is the work done by a machine on an object?
 a. power c. work output b. work input d. lever

3.

What is the work that you do on a machine?
 a. power c. work output b. work input d. lever

4.

What is the number of times the machine multiplies force?
 a. power c. mechanical efficiency b. output force d. mechanical advantage

5.

Which of the following in the comparison of a machine’s work output with the work input?
 a. mechanical efficiency c. mechanical advantage b. force d. power

6.

Which equation would you use to find mechanical advantage?
 a. MA = work output/work input ´ 100 b. MA = output force/input force c. MA = work input/work output ´ 100 d. MA = input force/output force

7.

Which of the following causes machines not to be 100% efficient?
 a. friction c. output force b. input force d. power

8.

In which situation is a person doing work on an object?
 a. A school crossing guard raises a stop sign that weighs 10 N. b. A student walks while wearing a backpack that weighs 15 N. c. A man exerts 350 N force on a rope attached to a house. d. A worker holds a box 1 m off the floor.

9.

Which of the following are simple machines used by the Egyptians to build pyramids?
 a. screws and screwdrivers c. plows and axes b. inclined planes and levers d. wheels and axles

10.

How does a ramp make lifting a heavy object easier?
 a. The object is moved over a shorter distance. b. The ramp increases the amount of work you do. c. Less force is needed to move the object over a longer distance. d. More force is needed to move the object over a longer distance.

11.

Which of the following is NOT a wedge?
 a. knife c. chisel b. plow d. ramp

12.

Where is the input force of a wheel and axle exerted?
 a. a circular distance c. an inclined plane b. a rectangular distance d. a spiral

13.

Greg applies a force of 100 N to move a box 5 meters. How much work did he do?
 a. 100 J c. 5 J b. 500 J d. 500 N

14.

If you exert 20 N of force on a screwdriver and it exerts 40 N on a paint can lid, what is the screwdriver’s mechanical advantage?
 a. 2 c. 1 b. 20 d. 40

15.

What two things must happen for work to be done?
 a. The object must move and there must be an output force. b. The object must move in the opposite direction of the force. c. The object must move in the same direction as the force. d. The object must move and the mechanical advantage must be greater than 1.

16.

A construction worker is lifting a load of bricks onto a truck. He does 200 J of work in 40 seconds. What is his power output?
 a. 50 J c. 50 W b. 5 J d. 5 W

17.

What type of simple machine is a screw?
 a. inclined plane c. lever b. wheel and axle d. pulley

18.

What is it called when a force causes an object to move in the direction of the force?
 a. energy c. work b. force d. power

19.

What is the rate at which power is transferred?
 a. power c. work b. energy d. joule

20.

What is a machine that is made of two simple machines?
 a. simple machine c. pulley b. lever d. compound machine