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 19 th 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