Work = F X D

Work:•Work is done when a force causes an object to move in the same direction that the force is applied.

Effort Doesn’t Always Equal Work:

• For work to be done, two things MUST happen

(1)Apply a force

(2)The object MUST move

What is the purpose of a simple machine?

•Reduce the amount of force

How much work did you do?

• The greater the amount of force applied, the greater amount of work done• More force = more work• AS LONG as the object moves• No movement = no work

Calculating Work:• Work (J) = Force(N) X Distance(m)• W = F X D• Work is calculated in Joules (J)• Joule = is named for James

Prescott Joule, a 19th century British physicist who showed that work and energy are related.

Calculating Work:• A weight lifter lifts a weight

with 500 N of force 2 meter above his head. How much work did he do?

• W = F X D• W = 500N X 2m• W = 1,000 J

Calculating Work:• A dinosaur chases its prey with

800 N of force for 10 meters. How much work did the dinosaur do?

• W = F X D• W = 800N X 1om• W = 8,000 J

Calculating Work:• A hockey puck travels for

5 meters and completed 10 J of work. With how much force was the hockey puck hit?

• W = F X D• 10 J = F X 5 m• F = 2N

Calculating Work:• A diver rides a sting ray.

She applies 10N of force and together they complete 50J of work. How far did she ride?

• W = F X D• 50 J = 10N X D• D = 5m