Hope this would help. :)

1. Work, Energy and
Power

2. Work
͏ A scalar quantity which refers to product of the
force and the displacement resulting from
application of force.
͏ W= Fd
͏ Unit: Joule (J) or kgm2/s2 or N*m

3. Energy
͏ Capacity to do work
1. Kinetic energy- energy of motion
• The net work done on an object is equal to its change in
kinetic energy.
• If work is done, KE increases. But, if this object does work on
another object, KE decreases.
2. Potential energy- energy at rest
• Gravitational Potential Energy
• Chemical Energy
• Elastic Potential Energy

4. Formula
KE= ½ mv2
Work= ½ m (Vf-Vi)2
GPE= work = mgh

5. Law of Conservation of Energy
~ Energy can neither be created nor destroyed
~Energy can be changed from one form to the other
~Energy can be changed into different forms but the total
energy of a system is constant
KE+PE = 0
KE= -PE

6. Power
 Speed of work or rate of doing work
 P= w/t
 P= Fv or F(d/t)
Unit: J/s or Watt (W)

7. Sample problems
1. A 98kg basketball player runs at a speed of 7m/s.
a) What is his KE?
b) How much work was done by the player to reach this speed starting
from rest?
2. A 2kg shell is shot from a cannon.
a) What is the GPE if the shell reaches a 450m in height?
b) What is the change in PE of the system when the shell falls to the
height of 300m?
3. Chito carries a 12kg knapsack while climbing a mountain. After 20
minutes, he is 6m above the foot of the mountain. If Chito weighs
6.8x102 N,
a) How much total work is done?
b) What is his power in kilowatts?