Work and Power

Potential Energy: Energy of Stored Position. Calculated by Mass X Gravity X Height. If Aiden’s Dog was 10 Kg on Earth, with a gravitional force of 9.8 m/s/s, and the height was 2m, how much potiential energy does the dog have?

Kinetic Energy: Energy of Movement and Motion Calculated by ½ Mass X Velocity^2 If Victoria was sliding a hill of 3m/s and the mass of the slide with her was 50 kg ’s, how much kinetic energy does the she have?

Law of the Conservation of Energy Energy cannot be created or destroyed; it can only be changed from one form of energy to another form.  The amount of total energy stays the same. 

Work Think about of all of the things you do on a daily basis that you consider “work.”

Work Work is done when a force moves an object or changes its direction. It is measured in Joules.

Work Work is done when a force causes an object to move in the direction of that force. Example: if you are forcing to hold the book bag up but moving forward= no Work. You have to move the book bag and force in the same direction (either lifting up or pushing forward to have work).

Work and Power Song

Rule for Work Work(Joules) = Force(Newtons) X Distance(meters) W = F X d

Now that you know what work is, refine your list to include only those things that are actually work.

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

Power Power is the rate at which work is done. Power is measured in Watts.

-To increase power, more work in a shorter amount of time. Rule for Power Power (Watts) = Work (Joules) / Time (seconds) P = W / T (So ONE Watt is 1J/Sec) -To increase power, more work in a shorter amount of time.

Example to Calculate 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 P= 4000 / 2 P= 2000 Watts