Science Chapter 3- Study Guide

Work

Work

Any time you exert a force on an object making it move some distance

What is equation for work?

Force times Distance

Joule

The work you do when you exert a force of 1 newton to move an object a distance of 1 meter

Power

The rate at which work is done

Watt

The unit of power when 1 joule of work is done in one second

Machine

Is a device that allows you to do work easier.

Input Force

The force you exert when you do work

Output Force

The force exerted on an object by a machine

Mechanical Advantage

a measure of how much a force is increased by using a tool or machine

Efficiency

The efficiency of a machine compares output work to input work.

simple machine

any of the basic mechanical devices for applying a force, such as an inclined plane, wedge, or lever.

inclined plane

simple machine consisting of a sloping surface, used for raising heavy bodies.

wedge

a triangular shaped tool, a portable inclined plane, and one of the six simple machines

Screw

a simple machine which appears like an inclined plane wound around a rod with pointed tip

fulcrum

the point on which the beam pivots

lever

a simple machine consisting of a beam or rigid rod pivoted at a fixed hinge, or fulcrum

pulley

comprises of a wheel on a fixed axle, with a groove along the edges to guide a rope or cable.

Wheel and axle

consists of a round disk, known as a wheel, with a rod through the centre of it, known as the axle

compound machine

a machine consisting of two or more simple machines

Which of these is work?

Pushing a heavy box or

Holding a heavy box

Pushing a box

What is mechanical advantage?

Mechanical advantage is the ratio of the output force to the input force. The actual mechanical advantage takes into account the amount of the input force that is used to overcome friction.

3 closely related simple machines in the inclined plane family

Inclined plane,screw, and

wedge

Equation for the mechanical of a wheel and axel

Radius of the wheel divided by the radius of the axel

Example of a wedge

Example of an inclined plane

Ramp on a truck

What is an example of a screw

A bottle cap

What is an example of a wheel and axel

Bike