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

Tags

NGSS.MS-PS3-1

NGSS.MS-PS3-4

NGSS.MS-PS3-5

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

Work is done on an object

• Only if the object moves

• 1. The force and movement are in the same direction

• 1. The displacement of the object is not zero

• 1. All of the above

What is the SI unit for work?

• Newtons

• Joules

• Grams

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

• No

• Yes

1. If a student carries a box across the room was work done on the box

• yes

• no

• 1. It depends on the mass of the box

• 1. It depends on the amount of time it took for the student to go across the room

Power is

• 1. work per unit time

• 1. represented by the symbol P

• 1. measured in Watts

• 1. all of the above

What is the unit of power?

• Watt

• Joule

• Newton

• Gram

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

• Work

• Job

• Machine

• Calculator

Tags

NGSS.MS-PS2-1

NGSS.MS-PS2-2

1. Simple machines decrease the amount of 

• 1. work done to perform a task

• 1. force required to perform a task

• 1. both a and b

• 1. neither a or b