Question

A car (of mass 1500 kg) and a small truck (of mass 2000 kg) collide suddenly at right angles at an icy intersection. The car was originally traveling eastward at 20.0 m/s and the truck was traveling northward at 20.0 m/s just before the collision took place. What is the speed of the combined wreck just after the collision if the vehicles become enmeshed?

Answer 1

Answer:

The answer is 20.0 m/s. Let's explain why.

Explanation:

In the crash problems, the key is that the total moment is the same before and after the crash

$P_{beforecrash}=P_{aftercrash}$

and P is defined as $P=mV$

Let's say the car has $m_{1}$ mass and $V_{1}$ speed and the small truck has $m_{2}$ mass and $V_{2}$ speed.

Total moment before the crash would be:

$m_{1} V_{1} +m_{2} V_{2}$

And after the crash the it equals $(m_{1} +m_{2})V_{combined}$

As we said before total moment is equal before and after the crash.

$m_{1} V_{1} +m_{2} V_{2}$=$(m_{1} +m_{2})V_{combined}$

$1500.20+2000.20=(1500+2000)V_{combined}$

Therefore

$V_{combined}=20$