Consider a stationary skater of mass 60 kg. Another skater of mass 40kg rushes and holds the first at a speed of 12km/hr. Both skaters hold together and move as one system (S) with a speed V.

Question

a) Determine V.
b) Determine the kinetic energy of (S) before and after collision.

Answer 1

conservation of momentum:
60(0)+40(12)=(60+40)V
solve for b.

Ke before= 1/2 40*12^2
KE after= 1/2 (100)V^2

Answer 2

Hoda