Why Pendulum Is Not Used for Measuring Time?

Since the time period of the pendulum depends on the gravity of earth and the pendulum clocks mainly works on local gravity so therefore the pendulum clock in the satellite will not give the correct time and so it is not used for measuring time in a spaceship orbiting the earth.

Can a pendulum be used to measure time?

A simple pendulum can be used to measure time.

Which is not used for measurement of time?

Therefore, a pendulum clock cannot be used for measuring time. So, (D)Pendulum clock is the correct answer.