1. Work
Ms. Jeffrey- Physics

2. Intro to work
When a force acts upon an object to cause a displacement of the object
Work was done upon the object
For a force to do work on an object, that force must have caused the displacement.
Examples
Pushing a cart in a grocery store
Pulling a sled

3. Is Work Being Done? A teacher applies a force to a wall.
A book falls off a table and free falls to the ground.
A waiter carries a tray full of meals above his head at a constant velocity.
A rocket accelerates through space.

4. Work Equation
Since work done on an object depends on Force and displacement, the equations for Work is:
W=F x d
Units of Work: [ N ] x [ m ]
1 Newton x meter = 1 Joule
Unit of Work is……. A Joule!
Where have we seen the unit Joule before?

5. Work Examples
How much work is done on the object below if it is displaced 5 meters?
How much work is done on the object below if it is displaced 10 meters?

6. Work and Energy Energy is the ability to do work on an object.
When work is done on an object, energy is transferred into the system.
More specifically, work is the change in kinetic energy of an object.
W= ∆ Ek

7. Work-Energy Example
A 500 kg car is moving at 28 m/s. The driver sees a barrier ahead. If the car takes 95 m to come to rest, what is the magnitude of the average force necessary to stop?