Question

An object of mass 7.60 kg is projected into the air at a 55.0° angle. It hits the ground 3.40 s later. Set "up" to be the positive y-direction. What is the y-component of the object's change in momentum while it is in the air? Ignore air resistance.

Answer 1

t = 1.70 sec time to rise to max height

Vy = 1.70 * 9.80 = 16.7 m/s speed at which it hits ground

Initial Y momentum = 7.60 kg * 16.7 m/s = 127 kg m / s

Total change of Y momentum = 2 * 127 kg m / s = 254 kg m / s