2. Energy
It is the ability to do work.
It is transferred by a force
moving an object through a
distance.
3. Energy and Work
Work and energy are closely
related.
*Work is a method of
transferring energy.
4. Energy and Work
• Energy can be transferred from one
place to another.
Examples:
1. Sound and light are transferred by
waves.
2. Electrical energy is transferred by
moving electrical charges through
a complete circuit.
3. Heat is transferred either by
randomly moving particles, or by
electromagnetic waves
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
moving.
6. Kinetic Energy
KE =
𝟏
𝟐
mv²
*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
object’s speed.
9. Solve:
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?