Question

A body of mass 10 kg starting from rest accelerates uniformly to a speed of 30

m/s in 10 s. Breaks is applied and the body stops in next 5 seconds. (1×4=4)​

Answer 1

Answer:

Given,

Mass (m) = 10 kg

Initial Velocity (u) = 0 m/s

Final Velocity (v) = 30 m/s

Time (t) = 10 s

1. Acceleration = v-u/t

= 30/10 m/s²

= 3 m/s²

Accelerating force = ma

= 10*3 N

= 30 N (Option A)

2. Initial Velocity (u) = 30 m/s

Time (t) = 5 s

Final Velocity (u) = 0 m/s

Retardation = u-v/t

= 30/5 m/s²

= 6 m/s²

Retarding force = ma

= 10*6 N

= 60 N (Option A)

3. Ratio of Acceleration to Retardation = 30:60

= 1:2 (Option B)

I hope this helps.