kinetic and potential energy

1. KINETIC
and
POTENTIAL
ENERGY

3. Work
- Is done when the force (F) applied to the
object causes the object to have a
displacement (d) in the same direction as
the force applied.
- Formula : W = Fd
W- unit of work
F – unit of force
d – unit of displacement
Unit of Work is Nm or joules, J

4. Sample Problem:
Suppose a woman is pushing a
grocery cart with a 500N force
along the 7m aisle, how much
work is done in pushing the cart
from one end of the aisle to the
other?

5. ENERGY
- is the ability or capacity
to do work

7. Two forms of Energy
Potential Energy
Kinetic Energy

8. Kinetic Energy
- the energy of a moving object
- Kinetic means movement
- when stored energy is being
used, it is making things move
or happen.

9. Examples of KE:

10. Equation of KE:
KE = ½ mv2
m- unit of mass (kg)
v- unit of velocity (m/s
2 )
KE – Nm or joules, J

11. Sample Problem:
A 1000 kg car has a velocity
of 17m/s. What is the car’s
kinetic energy?
What is the Kinetic Energy of
a 150 kg object that is moving
with a speed of 15 m/s?

12. 1. A 70 kg boy is running at about 10m/s. What
is his kinetic energy?

13. The faster the object
moves, the more
kinetic energy is
produced.

14. POTENTIAL ENERGY
- Is the energy stored in an
object.
- Potential simply means the
energy has the ability to do
something useful later on.

15. Example of Potential Energy:

16. Which object has more potential
energy?

18. Equation for PE
PE = mgh
m-unit of mass (kg)
g- gravity (9.8m/s 2)
h-height/displacement (m)
PE = joules, J

19. Sample Problem:
When a 1.0kg book is lifted
0.5meter from the table, what is
the potential energy?
 An object with a mass of 30kg is
placed on a hill top of height at
80meter. What is the potential
energy possessed by the object?

20. Solve the following problem:
1. Calculate the kinetic energy
of a 1000kg car travelling at
60m/s.
2. If a 0.2 kg ball is thrown with
a velocity of 6m/s, what is its
kinetic energy?

21. 1. What is the potential energy of a
0.15 kg ball lifted to a height of 2.0
above the ground?
2. A fruit hangs from a tree and is about
to fall to the ground of 10m height. It
has a PE of 32.5 J. Calculate the mass
of the fruit.
3. A mass of 20kg is taken from the
ground to the height of 255m. Find the
potential energy of the object.