Work and Machines

What is the definition of work?

• A job that completes a task

• Energy transferred when a force makes an object move

• Earning money

• Using a computer

If you push against an object and it doesn't move, are you doing work?

• No

• Yes

In order for work to be done, what two things need to happen?

• Object needs to move in any direction

• Object needs to have acceleration and speed

• Object must move and must move in the direction of the force applied

• Object needs to feel force, it doesn't matter if it moves

A ___________ is a device that changes the force or increases the motion from work.

• Work

• Job

• Machine

• Calculator

What is the SI unit for work?

• Newtons

• Joules

• Grams

The purpose of machines is to _______________.

• Make us look cool

• Make work easier

• Change the way work is done

_____________ is a measure of how much of the work is changed into useful work

• Efficiency

• Energy

• Joule

• Newton

What is the equation for efficiency (%)

• output work divided by input work x 100

• input work divided by output work x 100

• output work divided by net force x 100

• Input work divided by net force x 100

work = force x distance

• TRUE
• FALSE

Using 10 N of force to move a box 2 m,
= how much work?

• 0 (zero) J
• 20 J
• 12 J
• 8 J