Question

Consider a pendulum swinging. Which type(s) of energy is/are associated with the pendulum in the following instances:

the moment at which it completes one cycle:
a) Potential energy
b) Kinetic energy
c) Both a and b
d) Neither a nor b

just before it begins to fall back towards the other end:
a) Potential energy
b) Kinetic energy
c) Both a and b
d) Neither a nor b

the moment that it is in the middle between the two ends:
a) Potential energy
b) Kinetic energy
c) Both a and b
d) Neither a nor b

just before it reaches the end of one cycle (before step 1):
a) Potential energy
b) Kinetic energy
c) Both a and b
d) Neither a nor b

Answer 1

In the context of a swinging pendulum, at the highest points it has maximum potential energy, in the middle of the swing it has maximum kinetic energy, and just before reaching the end of a cycle, it has a mix of both energies.

Step-by-step explanation:

Considering a pendulum swinging, different types of energy are associated with the pendulum at different points in its cycle:

• At the moment at which it completes one cycle (the highest point), it has maximum potential energy and minimum kinetic energy because it momentarily stops before changing direction.
• Just before it begins to fall back towards the other end, the pendulum again has maximum potential energy and minimum kinetic energy for the same reason as above.
• The moment that it is in the middle between the two ends is the point of maximum kinetic energy because it is at its fastest, and it has the least potential energy.
• Just before it reaches the end of one cycle (before step 1), the pendulum has a combination of both potential and kinetic energy, as it is both moving and elevated above the lowest point of its swing.