Chapter 5, Problem 19Q

To determine

To Choose:The correct option.

Explanation of Solution

Introduction:

Let R be the apparent weight of a person having mass m. if a is acceleration of the elevator, then:

(i) The apparent weight of the person in the elevator when it accelerates upward:

  $R=mg+ma$

(ii) The apparent weight of the person in the elevator when it accelerates downwards:

  $R=mg\text{ -}ma$

(iii) In case of free fall,

  $\begin{array}{l}a=g\\ R=0\end{array}$

(iv) When the elevator moves upwards with a constant speed, acceleration of the elevator will be zero,

  $\begin{array}{l}a=0\\ R=mg\end{array}$

The apparent weight would be greatest in case when elevator accelerates upwards. Option (b) is correct.

The apparent weight would be least in case of freefall. So, option (c) is correct.

The apparent weight be same as that on the ground when elevator moves upward with constant speed. So, option (d) is correct.