Two 2.0kg bodies a and b collide the velocities before the collision are u1=15i+30j and u2=-10j+5.0j after the collision v1=-5.0j+20j all speeds are given in meters per seconds find the final velocity and how much kinetic energy is gained or lost in the collision

Use the law of conservation of momentum. Since the momentum is a linear measure, we can treat each of the dimension separately:

i-direction:

j-direction:

Final velocity is: (10i + 15j) m/s

Change in the kinetic energy:

The system lost 500J worth of kinetic energy in the collision

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