Force acts for 20 s on a body of mass 20 kg, starting from rest, after which the force ceases and then body describes 50 m in the next 10 s. The value of force will be :40 N5 N20 N10 N

To solve this problem, we need to use the second law of motion, which states that the force acting on an object is equal to its mass times its acceleration (F = ma).

First, we need to find the acceleration of the body. We know that the body travels 50 m in 10 s after the force ceases. This means that the body continues to move with the same velocity it had when the force stopped acting.

The velocity (v) of an object can be calculated using the formula v = u + at, where u is the initial velocity, a is the acceleration, and t is the time. In this case, the initial velocity (u) is 0 (since the body starts from rest), and the time (t) is 20 s.

So, we can rearrange the formula to solve for acceleration (a): a = (v - u) / t.

The velocity (v) when the force stops acting is the distance (s) divided by the time (t), which is 50 m / 10 s = 5 m/s.

So, the acceleration (a) is (5 m/s - 0) / 20 s = 0.25 m/s².

Finally, we can find the force (F) using the formula F = ma, which gives us F = 20 kg * 0.25 m/s² = 5 N.

So, the value of the force is 5 N.