Caution! Slippery Surface!
You went to a park in winter to practice ice skating in a frozen lake, but because you're a beginner, you asked your friend to give you some impulse to start.
He applied a force of 150 Newtons to you during 1.2 seconds, after which you began moving with a constant velocity.
Another person is skating toward you with a velocity of 5 m/s. Unable to stop, you both collide and both stop moving.
Suppose that you have a mass of 60kg. Find the mass (in kilograms) of the person who collided with you.
Details and assumptions: Because the lake is frozen, the icy surface causes negligible friction.