Question

A body of mass 5 kg is moving in a straight line. The relation between its displacement and time is x = (t³ - 2t - 10)m. What is the force acting on it at the end of 5 second?

Options

• 120 N

• 80 N

• 150 N

• 100 N

Answer 1

150 N

Explanation:

x = t³ - 2t - 10

`dx/dt=3t^2-2`          `(d^2)/(dt^2)=6t`

`|("d"^2x)/("dt"^2)|_5=30`     m = 5 kg

∴ F = 5 × 30 = 150 N