A hockey ball of mass 200 gram travelling at 10 m/s is struck by a hockey stick so as to return it along with original path with a velocity at 5 m/s . Calculate the change of momentum Orchid in the motion of the hockey Ball by the force applied by the hockey stick.
How did the change of momentum have postive sign?
he Mass of Hockey ball, m | = 200 g = 0.2 kg |
Initial velocity, u | = 10 ms−1 |
Final velocity, v = −5ms−1 | |
Initial momentum, p1 | =mu = 0.2 ×10 = 2 kg ms−1 |
Final momentum, p2 | =mu = 0.2 ×(−5) = &minus1 kg ms−1 |
∴ Change in momentum | =p2−p1 |
=&minus1 kg ms−1 − 2 kg ms−1 | |
=− 3 kg ms−1 | |
The negative sign shows a change in direction of hockey ball, along the return path after strike |