Chapter 3: Work & Machines

Question 0

Joule

Answer 0

The SI unit of work

Question 1

Work

Answer 1

Any time you exert a force on an object that causes the object to move some distance.

Question 2

Power

Answer 2

The rate at which work is done

Question 3

Watt

Answer 3

The unit of power when one joule of work is done in one second.

Question 4

Machines

Answer 4

A device that changes the amount of force exerted, the distance over which a force is exerted, or the direction in which force is exerted.

Question 5

Input Force

Answer 5

The force exerted on a machine.

Question 6

Output Force

Answer 6

The force exerted on an object by a machine.

Question 7

Mechanical Advantage

Answer 7

The number of times a machine increases a force exerted on it.

Question 8

Efficiency

Answer 8

The percentage of the input work that is converted to output work.

Question 9

Simple Machine

Answer 9

The most basic device for making work easier, these are the smaller building blocks for complex machines.

Question 10

Inclined Plane

Answer 10

A simple machine that is a flat, sloped surface.

Question 11

Wedge

Answer 11

A simple machine that is an inclined plane that moves.

Question 12

Screw

Answer 12

A simple machine that is an inclined plane wrapped around a central cylinder to form a spiral.

Question 13

Lever

Answer 13

A simple machine that consists of a rigid bar that pivots about a fixed point.

Question 14

Fulcrum

Answer 14

The fixed point around which a lever pivots.

Question 15

Pulley

Answer 15

A simple machine that consists of a grooved wheel with a rope or cable wrapped around it.

Question 16

Wheel & Axle

Answer 16

A simple machine that consists of two attached circular or cylindrical objects that rotate about a common axis, each one with a different radius.

Question 17

Compound Machine

Answer 17

A device that combines two or more simple machines.