Page 212 - Physics

Physics for Secondary Schools

5. Using a metre rule measure and Potential energy
record the distances (d) that the
wooden block moves as it is pushed Potential energy is the energy possessed
by the rolling metal ball. by an object due to its position.
6. Repeat steps 2 to 5 for the values of
h = 80 cm, 60 cm, 40 cm and 20 cm. An object can have potential energy if it is
Record your results as in Table 9.1. acted upon by a restoring force that tends
Table 9.1 to restore it to its initial position after it
has been displaced. For example, a body
h (cm) d (cm) raised from the ground to a certain height

100 has gravitational potential energy due to
80 gravitational force. On release, it returns to
60 the ground, thus its potential energy relative
40 to the ground becomes zero. Another type
20 of potential energy is due to elastic force
in a compressed spring (Figure 9.13). This
7. Plot a graph of distance d (cm)
against the height h (cm). is elastic potential energy.

Questions

(a) Discuss how the height of the raised
end of the tube and the distance that the
wooden block is pushed are related.
(b) what would be the effect of the ball’s
mass on the distance travelled by the
ball if the height is kept constant?
Explain your answer. Figure 9.13: Compressing spring

A walking elephant in Figure 9.12 has high Several restoring forces lead to various
kinetic energy because of its large mass. If types of potential energies. Two types
one collides with a walking elephant, part of potential energy are briefl y discussed
of its kinetic energy can be transferred to here.
the person, resulting in serious injuries.
Elastic potential energy
This is the energy stored in objects like
springs as a result of reversible deformation.
When a force is applied to a spring, it gets
compressed or stretched. But when the
force is removed, it regains its original
shape and size. In the deformed state, the
spring has elastic potential energy.
Figure 9.12: A walking elephant

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Student’s Book Form One

Physics Form 1 Final.indd 206 16/10/2024 20:58