Question

Consider two bodies with masses 2kg and 5kg respectively. Both the bodies are at rest and the same force is acting on both the bodies. What is the ratio of times that is required to reach a final velocity?
(a) 2:5
(b) 25:4
(c) 5:3
(d) 4:25

Answer 1

GIVEN

Masses of two body = 2kg & 5kg

SOLUTION

We know

Force = Mass × Acceleration

Acceleration = Force/Mass

» a1 = F/2

» a2 = F/5

From equation of motion we get

v = u + at

Since intial velocity is 0 i.e u = 0

v = at

v1 = F/2 t1 -----(A)

v2 = F/5 t2 -----(B)

According to question,

v1 =v2

F/2 t1 = F/5 t2

t1/t2 = F/5 × 2/F

t1/t2 = 2/5

RATIO OF TIMES = 2 : 5

» Answer is Option A

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