4. Energy and Work
• Energy can be transferred from one
place to another.
1. Sound and light are transferred by
2. Electrical energy is transferred by
moving electrical charges through
a complete circuit.
3. Heat is transferred either by
randomly moving particles, or by
5. Kinetic Energy
• It is the energy of a moving
object or energy in motion.
• The word kinetic comes
from the Greek word
kinetikos which means
6. Kinetic Energy
*doubling the mass in the formula
would double the KE. However,
Doubling the speed would
quadruple the KE, since KE is
proportional to the square of an
1. A 1000kg car has a velocity of 17m/s.
What is the car’s KE?
2. A 70.0 kg man is walking at a speed of 2.0
m/s. What is his KE?
3. A 1400 kg car is moving at a speed of
25m/s. how much KE does the car have?
4. A 50.0 kg cheetah has a KE of 18000 J. How
fast is the cheetah running?