1. April 8, 2009
What is the potential energy in the following situations:
4 kg object at a height of 6 m
4 N object at a height of 6 m
Fill in the blanks:
Gravitational Potential Energy is __________ proportional to _________ and height.

2. Goals To explain different types of energy
To calculate potential and kinetic energy

3. Equation: GPE = m x g x h h = 35 m m = 65 kg g = 9.8 m/s2 GPE = ?
PRACTICE PROBLEM: Find the PE of a rock climber as she climbs 35 m above the base of a cliff. Her mass is 65 kg.
Equation:
GPE = m x g x h
Given:
h = 35 m
m = 65 kg
g = 9.8 m/s2
GPE = ?
Solve: GPE =
65 kg x 9.8 m/s2 x 35m
=22,295 J

4. Q: What is KINETIC ENERGY?
Kinetic Energy (KE) is the energy due to an object’s motion
Active energy
A rock as it falls off of a cliff
Formula: KE = ½ * m * v2
m= mass (kg)
v = velocity (m/s)
UNITS:

5. PRACTICE PROBLEM: What is the KE of a 44 kg Cheetah running at 31 m/s?
Given:
m = 44 kg
v = 31 m/s
KE = ?
Equation:
KE = ½ * m * v2
Solve: KE =
(1/2) (44 kg) (31 m/s)2
21,142 J

6. Homework
Kinetic and Potential Energy WS