Physics
A pendulum is oscillating on either side of its rest position. The correct statement is :
- It has only the kinetic energy at its each position.
- It has the maximum kinetic energy at its extreme position.
- It has the maximum potential energy at its mean position.
- The sum of its kinetic energy and potential energy remains constant throughout the motion.
Answer
The sum of its kinetic and potential energy remains constant throughout the motion.
Reason — The sum of kinetic and potential energy does not remain constant throughout the motion of a pendulum. It varies as the pendulum swings due to the interconversion of kinetic and potential energy. However, the sum of kinetic and potential energy is constant if we consider the entire system (kinetic energy + potential energy = mechanical energy), as long as there are no external forces like friction acting on the pendulum.
Related Questions
A spring is compressed storing potential energy. When the spring is released it propels an object forward. What change would you notice in the total mechanical energy of the system?
- It increases
- It decreases
- It becomes zero
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A a body is released from a height. During its motion in striking the ground, the quantity which does not change is:
- momentum
- kinetic energy
- potential energy
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A simple pendulum while oscillating rises to a maximum vertical height of 7 cm from its rest position where it reaches its extreme position on one side. The mass of the bob of simple pendulum is 400 g and g = 10 m/s2. The total energy of the simple pendulum at any instant while oscillating is:
- 0.28 J
- 2.8 J
- 28 J
- 28000 J
A block slides down a frictionless incline. The sum of its P.E. and K.E. at every point :
- increases
- decreases
- remains constant
- first decreases and then increases