Energy, Work & Power How the world works….

Energy The ability to cause CHANGE Anything that causes change must have ENERGY!! There are many types of energy You use energy to function

Work and Energy Another way to think about energy is: -ENERGY is the ability to do WORK -If something has energy, it can transfer it to another object by doing work on that object. -When you do WORK on something, you INCREASE its ENERGY -Energy is always transferred from the object doing work to the object on which work is done.

Define / Describe WORK Work is done when a force causes an object to move in the direction that the force is applied. The formula for work is: W = F X D If there is no movement, there is no work

Work or Not?

Two things must happen for work to be done. A force must be applied to an object The object must move in the same direction as the force.

Joules? Work is measured in Joules. Rule for Work Work (Joules) = Force (Newtons) X Distance(meters) W = F X d Example to calculate Work Question: A weightlifter raises weights of 2000 Newtons from the floor to a height of 2 meters. How much work has been done? Answer: W = F X d W = 2000 X 2 W = 4000 Joules

Example Problem You push a refrigerator with a force of 100 N. If you move the refrigerator a distance of 5 m, how much work do you do?

What is Power? Power is the rate at which work is done. Power is measured in Watts. Rule for Power Power (Watts) = Work (Joules) / Time (seconds) P = W / T Example of calculating Power Question: A weightlifter lifted 2000 Newtons to a height of 2 meters. This 4000 Joules of work. What is the power output if this was done in 2 seconds? Answer: P = W / T = 4000 / 2 = 2000 Watts

Think about it like this……. = The amount of work done in one second/the RATE at which WORK is done POWER For example: If you and a friend push two boxes (identical in mass) for the same distance = YOUR WORK DONE IS EQUAL BUT: If your friend pushes the box faster than you, your friend is MORE POWERFUL!

Vocabulary Energy Work Power Joules Watts