Question

A body of mass 5 kg is moving with velocity of v=2i+6j

Answer 1

change in velocity is final - initital

Given initital = 2 i + 6 j

Final = 10 i + 6 j

Hence change = 10 i + 6 j - (2 i + 6 j) = 10 i + 6 j - 2 i - 6 j = 8 i (after cancelling j terms)

Hence change in momentum of the body = mass * velocity change

= 5 * 8 i = 40 i

Whose magnitude will be 40 kg m/s and direction is along positive x direction...