Question
A body of mass 10 kg is moving with a velocity of 100 m/s. Find the force needed to stop it in 5 seconds.
[Ans: 200 N]
Solution
Mass (m) = 10 kg
Initial velocity (u) = 100 m/s
Final velocity (v) = 0 m/s
Time (t) = 5 seconds
Force = m×(v - u)\over t
= 10 × (0 - 100)\over 5
= 10 × (- 100)\over 5
= – 200 N
The negative sign indicates that the Force is in the opposite direction to the motion of the body.
