Answer:
The P.E of the pendulum is, P.E = 15 J
Explanation:
Given data,
The length of the pendulum, l = 3 m
The maximum angular displacement from vertical, Ф = 10°
The K.E at its lowest position is, K.E = 20 J
The total mechanical energy of the system is equal to the sum of its K.E and P.E
E = K.E + P.E
At the lowest position P.E = 0
Therefore, The total mechanical energy,
E = 20 J
When the K.E of the pendulum is K.E = 5 J
E = K.E + P.E
P.E = E - K.E
= 20 - 5
= 15 J
Hence, the P.E of the pendulum is, P.E = 15 J
