Question

find the net force acting with respect to time see the pic

Answer 1

Hello Friend.........☺
P = ln t + 1/t
Taking derivative on b/s....
F = 1/t - 1/t^2
As net force is zero
1/t -1/t^2 = 0
1/t ( 1- 1/t) =0
1 -1/t =0
1/t = 1
t = 1s
THIS is your answer.....