Question

A mass is hanging on a spring balance which is kept in a lift. The lift ascends. The spring balance will show in its readings

(a) an increase

(b) a decrease

(c) no change

(d) a change depending on its velocity

Answer 1

Correct Answer : (a) an increase

Explanation:

Let acceleration of lift = a and

let reaction at spring balance = R

Applying Newton’s law

R – mg = ma 

⇒R = m(g + a)

thus net weight increases, so reading of spring balance increases.