Question

A motor is fixed inside a box which is moving upwards with velocity 5 m/. String is winding at the rate 3 m/. Then the velocity of block A will be:

(A) 2.5 m/ downwards 2.5 m/

(B) 5 m/ downwards 5 m/

(C) 1 m/ downwards 1 m/

(D) 2 m/* downwards

Answer 1

*Correct option (C) 1 m/ downwards**

Explanation:

Velocity of a point on spring near motor VM = 5 m/*

upwards

– 3m/ downwards = 2m/

upwards From constrant relation