Question

force of 4N is applied on body of mass 20kg the work done in 3rd second is​

Answer 1

Answer:

Explanation:

Work done will be 0 because body will not accelerate.

Answer 2

Answer:

Given force = 4 N

mass of body = 20 kg

We know,

F = ma (2nd law of Newton)

So,

a = F/m = 4/20 = 1/5 m/s^2

Time taken = 3 s

S(3) = displacement = 1/2 at^2 = 1/2 × 1/5 × 3^2

S(3) = 9/10 = 0.9 m

Displacement in 2 s = 1/2 at^2

S(2) = 1/2 × 1/5 × 2^2 = 4/10 = 0.4 m

Hence,

displacement in the 3rd second = S(3) - S(2)

S = 0.9 - 0.4 = 0.5 m

Now,

work done = F.S = 4 × 0.5

W = 4 × 5/10 = 20/10 = 2 Joules