Mechanical advantage and Work

How is work defined?

• the amount of energy 
• the transfer of force over a distance
• rate of work in a given time
• the change in distance in a given time

What is the unit of measurement for work?

• Newtons
• Joules 
• Watts
• Meters

Which of the following is an example of work being done?

• Teacher sitting in a chair
• Book resting on desk
• Keys hanging from a key chain
• A ball being rolled on the floor

If a student uses 10 Newtons of Force to push a chair 5 meters, how much is work is being done?

• 2 Joules
• .5 Joules
• 50 Joules
• 20 Newtons

Is this an example of work?
A teacher applies a force to a wall and becomes exhausted.

• True
• False

Is this an example of work? 
A waiter carries a tray full of meals above his head by one arm straight across the room at constant speed. 

• True
• False

Is this an example of work? 
A rocket accelerates through space.

• True
• False

What is a machine?

• an object that has AI

• an object that is designed to take over the earth in 2020

• a device that changes force

• a mechanism that is used to decrease the amount of work done

What is mechanical advantage?

• The advantage a machine has over a bicycle

• A measure of how much a simple machine reduces work

• A measure of when is the best time to use a simple machine

• the number of times a machine increases input force

What is effort (input) force?

• the force one exerts on a machine

• the force which an effort force must overcome in order to do work on an object via a simple machine.

• the force the machine exerts on a object

• the output work times the input distance