Question

A Truck moving West at a velocity of 43 m/s collides with a stationary car with exactly 1/5 of its mass. is there two vehicles all together, calculate the magnitude of the velocity of the combined mass immediately after collision

Answer 1

conserve momentum (mv)

6/5 the mass, so 5/6 the velocity = 5/6 * 43 = ___ m/s
or, more methodically,
m*43 + (m/5)*0 = (m + m/5)*v