Answer:
v = -24.5 m/s
Explanation:
Use conservation of momentum P = m*v. Unless there are external forces involved, total momentum must be conserved.
P: momentum
m: mass
v: velocity
1. calculate the total momentum before the collision:
[tex]P=m_{car}v_{car} + m_{truck}v_{truck}[/tex]
2. the total momentum after the collision must not change:
[tex]P_{before}=P_{after}[/tex]
3. after the collision the velocity of the car is the same as the velocity of the truck:
[tex]v = v_{car} = v_{truck}[/tex]
4. combining 2. and 3.:
[tex]P= (m_{car}+m_{truck})v[/tex]
5. this equation only has one unknown and can be solved for v:
[tex]v = \frac{P}{m_{car}+m_{truck}} =\frac{m_{car}v_{car} + m_{truck}v_{truck}}{m_{car}+m_{truck}}[/tex]
[tex]v=\frac{800*15 + 1500 * (-45.5)}{800 + 1500} = -24.5[/tex]
