# Chapter 14 Simple Machines, Work, and Power

## 44 terms

Distance

### A ___ (_____ ______) is equal to one joule.

NM (Newton Meter)

Joules (J)

Simple

### Machines make work easier by changing the _____ of the ______ exerted or the _________ of the force or both.

Size of the force
Distance of the force

Effort

Resistance

Efficiency

Friction

Effort

Resistance

Input

Output

### What is the formula for work input?

Wi = Fe*dE
Work input = Effort force * Effort Distance

### What is the formula for work output?

Wo = Fr*dR
Work output = Resistance force * Resistance Distance

### What is the formula for mechanical advantage?

MA = Fr/Fe
Mechanical advantage = Resistance force / Effort Force

### What is the formula for efficiency?

EFF = Wo / Wi*100%
Efficiency = Work output / Work input * 100%

### What is the formula for power? (More than one)

P = W / T
Power = Work / Time
or
P = F*D / T
Power = Force * Distance / Time

Power

Horsepower

750

1,000

Lever

### What is an example of a first class lever?

See saw, pliers, and scissors

### What is an example of a second class lever?

Wheel barrow, door, and paper cutters

### What is an example of a third class lever?

Bat, broom, and oar

Fixed

Fixed

Moveable

Moveable

Inclined plane

Wedge

### To increase the mechanical advantage you make the wedge _________, ________, or even __________ it.

Longer, thinner, or even sharpen it

Compound

### __________ ______- Where the fulcrum is between the effort and resistance force.

First Class Lever

### __________ ______- Where the resistance is located between the effort force and fulcrum.

Second Class Lever

### _________ _______- Where the effort force is between the resistance force and fulcrum.

Third Class Lever

### What are the six types of simple machines?

A lever, pulley, wheel & axle, screw, inclined plane, and wedge

### Power is measured in __________ per _______ or _______.

Joules per second or watts

Pulley