1. Conservation of Energy & Power
Work, Energy & Power
Conservation of Energy & Power

2. Conservation of Energy
Law of conservation of energy:
“Energy cannot be created nor destroyed”.
Therefore:
Where 1 is the initial state, 2 is the final state.
*ET = Total energy (J)

3. Example #1
What is the final velocity of a ball, initially traveling on the ground at a speed of 15m/s, after rolling up a 3m high hill?

4. Power Power: The rate of doing work or transferring energy.
Measured in Watts (W)
1 W = 1 J / s (joule per second)
It is given by:
Watts are commonly used to measure the power used by electrical appliances.
Where:
P=power (W)
W = work (J)
∆E = Energy transferred (J)
∆t= time interval (s)

5. Example #2
How much power is required to lift a 10kg mass 2m above the ground if it takes 0.5 s?

6. Power & Velocity
By using the definition of power, we see an interesting relationship with the velocity of an object:
*accelerated
motion
*uniform motion OR