Bell Ringer What does the word work mean to you? What are three examples of work? 1 2 3

Work Work is done only when force is applied to an object and the object moves in the same direction as the applied force. If the object doesn’t move, then no work is happening.

Work SI Unit for work is the Joule (J) The equation for work is: W=F x d W= Work F= Force (N) d= distance (m)

Power Power measures the rate at which work is done or energy is transferred. Power Equation P=W t P= Power W= Work t= Time

Power The SI Unit for power is the watt (W). Warning- The symbol for work is “W.” The symbol for watt is “W.” Don’t get them confused.

Machines Machines help people do work by changing the size of an input force, the direction of the force, or both. Changing the direction, or size of input force is called multiplying the force. Machines don’t change the amount of work being done, just the force required to do the work.

Mechanical Advantage Some machines like ramps make work easier by multiplying the force that is applied. Mechanical Advantage is the ratio between the input force and the output force. Pushing a box up a ramp and into a truck requires less force than lifting it into the truck. The same amount of work is done either way.