question_answer

A \[60\text{ }kg\]man stands on a spring scale in a lift. At some instant he finds that the scale reading has changed from \[60\text{ }kg\] to \[50\text{ }kg\] for a while and then comes again to \[60\text{ }kg\] mark. What should he conclude?

A)  The lift was in constant motion upwards

B)  The lift was in constant motion downwards

C)  The lift while in motion suddenly stopped

D)  The lift while in motion upwards suddenly' stopped

Correct Answer: D

Solution :

When lift falls with acceleration  or rises with retardation \[(-a),\] then a person apparently loses weight.        In the given case scale reading changes from \[60\text{ }kg\]to \[50\text{ }kg\]for a while and then comes back to    \[60\text{ }kg\]mark. It happens while the lift in motion upwards suddenly stops.