Work

• Work is energy transferred that causes the object to move in the direction of the force — no movement, no work.

• Formula for work: W = F x d

• Units: – Work – joule (J)– Force – newton (N)– Distance – meter (m) or depends on problem

• Power is the rate at which work is done

• Formula: P = W/t

• Units:– Power – watt (W)– Work – joule (J)– Time – seconds (depends on problem)

Machines

• Machine – device that makes work easier by changing the size or direction of the force

• Machines let you swap force for distance or distance for force….you still do the same amount of work

Levers – move from a fixed point

Pulleys – grooved wheel that holds rope or cable

Wheel and axle – 2 circular objects of different sizes (wheel is larger)

Inclined plane – straight slanted surface

Wedge – two inclined planes that move

Screw – inclined plane wrapped around a cylinder

Compound machine – made of more than one simple machine