1. GRAVITATIONAL POTENTIAL & KINETIC ENERGY
Work, Energy & Power
GRAVITATIONAL POTENTIAL & KINETIC ENERGY

2. Work Recall: Calculated by Work is the change in energy of a system.
Positive work > System ends up with more energy.
Negative work > System ends up with less energy.
Calculated by
Where:
W = Work (J)
F = Force in direction of motion (N)
d = distance (m)

3. Gravitational Potential Energy
The type of energy possessed by an object because of its height above ground.
To lift an object using work: M ∆h
*Force to lift is force of gravity
*Since doing work changes energy
in system.
Where:
EG=Gravitational Potential Energy (J)
m = mass (kg)
∆h= height (m) (starts on ground)

4. Example 1
Calculate the gravitational potential energy of a 15kg object 2.3m above the ground.

5. Kinetic Energy The type of energy due to an object’s motion.
Calculated by:
Units of Kinetic Energy are Joules (J).
Where:
EK= Kinetic Energy (J)
m = mass (kg)
v= velocity (m/s)

6. Kinetic Energy & Work Using work: *Kinematics formulae
*Diff of squares

7. Example #2
What is the mass of a bullet traveling at 360 km/h with 750 J of kinetic energy?