Question

Same force acts on two bodies of different masses 2 kg and 4 kg initially at rest. the ratio of times required to acquire same final velocity is 

(A) 2 : 1 

(B) 1 : 2 

(C) 1 : 1 

(D) 4 : 16

Answer 1

Correct option: (B) 1 : 2

Explanation:

F = ma

same force is acting on both masses.

 F = m₁ a₁ = m₂ a₂ = constant

(a₂ / a₁) = (m₁ / m₂)

also v = v_o + at

here v_o = 0

v = at

v = a₁ t₁ = a₂ t₂ = constant

(t₁ / t₂) = (a₂ / a₁)

Hence (t₁ / t₂) = (a₂ / a₁) = (m₁ / m₂) = (1 / 2) = 1 : 2