Posted by Alex on .
A 2.00kg bullet moving at 600m/s strikes a piece of wood at rest on a frictionless table. The bullet sticks in the wood and the combined mass moves slowly down the table. a.) What is the speed of the combined mass after the collision? b.)What is the change in kinetic energy of the system? c.) What is the percentage of kinetic energy lost in the collision?

physics 
Elena,
The case of inelastic collision
m1•v1+m2•0=(m1+m2)•v
v= (m1•v1)/ (m1+m2).
It is necessary to know the mass of a piece of wood m2.
The change in kinetic energy is
ΔK=K1K2 = m1(v1)^2/2  (m1+m2)v^2/2.
For finding the percentage
((K1K2)/K1) •100%