Page 5 - TRIAL 2

1. Kinetic energy is the energy an object A truck is moving with a velocity of 13 km/hr. If the
possesses due to its motion. Any object which mass of the truck is 8000 kg, calculate the kinetic
is moving has kinetic energy. energy possessed by the truck.

2. The kinetic energy of a moving object depends
Solution
on its mass and velocity. 13 1ℎ 1000
= × ×
2
Kinetic energy, K.E = ½ mv ℎ 3600 1
= 3.5/
Where;
1
2
. =
m = mass of an object 2 1
2
. = (8000)(3.5)
v = velocity of the object 2
= 42,875
3. This equation reveals that the kinetic energy of

an object is directly proportional to the square

of its speed. That means if velocity is increased
Potential Energy
twofold, the kinetic energy will increase by a

factor of four.
1. Potential energy is the energy possessed by an
4. For example, the same car with the mass of object due to its position or state.
1200 kg, is moving with different velocity
2. Gravitational potential energy is part of
potential energy.

3. Gravitational potential energy is the energy
v = 5 m/s which an object has because of its position

4. This energy is depends on

a) Its mass
b) Its height
v = 20 m/s
c) The gravitational field.
5. For examples, given a same mass of an object,

with velocity, v  5m/s but with a different height.

Kinetic energy  1  1200 5 2 The gravitational potential
2 energy is 100%
 15kJ
Two objects having the same mass
with velocity, v  20m/s Δh

Kinetic energy  1  1200 20 2 The gravitational
2
 240kJ potential energy is 0%

5. From the examples above, it can be conclude
that a car with higher velocity will have a higher 6. Gravitational potential energy , E.P
kinetic energy. The high kinetic energy of a car E.P = m g h
often causes serious, injuries when an accident
m = mass
occurs. Therefore, it is important for user to
drive carefully at lower velocity. g = acceleration due to gravity
h = change in the height of the object
Example 1

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