Question

In order to find the time, an astronaut orbiting in the earth satellite should use:

• A. A pendulum clock
• B. A watch having main spring to keep it going
• C. Either a pendulum clock or a watch
• D. Neither a pendulum clock nor a watch

Answer 1

The correct option is B A watch having main spring to keep it going

Stop watch and hourglass is not used to read time, it is useful for measuring time intervals only.
In a pendulum clock and an hourglass, the time period depends on the value of g. In an orbiting satellite, the pendulum will experience free fall and feel weightlessness due to which g = 0. Hence, its time period will be infinite or it will not oscillate.
In a spring watch, the time period is independent of the value of g and only depends on the spring. So, in order to find the time, an astronaut orbiting in the earth satellite should use a spring watch.