A subcompact car, mass 1,000 kg, runs into and sticks to an at rest, 2,200 kg SUV. If their final speed is 4.7m/s ,what was the smaller cars initial speed?

Question

a) 67 m/s
b) 30m/s
c) 2.2 m/s
d) 15 m/s

Answer 1

final momentum = 4.7 (1000+2200)=15040

initial momentum = 1000 v
so
v = 15.04 m/s

Answer 2

15 m/s