a 500 kg truck moving at 30 m/s strikes a parked car. they connect together and move forward.?

Question

1) what is the momentum of the truck before it stirkes the car?
please show formula
2) what is the speed of the car and the truck as they move forward (connected together) after the collision?
please show formula

Answer 1

1) momentum of the truck=mv=30 * 500 =15000 Kgm/s
2) it depends of the weigth of the parked car. if we name it m2, the solution is:
total momentum before strike=total momentum after strike
m1v1 + m2v2 = (m1+m2)V
where:
V = the speed of two car after strike
m1= mass of truck
m2 = mass of parked car
v1=velocity of truck before strike
v2 = velocity of parcked car before strike = 0

15000 + 0 = (500 + m2) * V

V= 15000/(500 + m2)

Answer 2

momentum, p == mv
Momentum of the truck = 30*500 = 15,000 kgm/sec
Momentum of the combination must be the same, as the car was initially at rest, so
v = 500/(500 + Mc), where Mc is the mass of the car in kg.