JEE Main Physics question
A body of mass 6 kg moves in a straight line according to the equation x = t³ − 75t, where x is in metres and t in seconds. The force on the body at t = 4 s is
Answer: (C)
Solution
v = 3t²−75, a = 6t. At t=4: a=24 ms⁻². F = ma = 6×24 = 144 N.