Question

An empty maglev train car of mass M1= 24.2 metric tons and moving at a speed v1= 26.4 mph is hit from behind by another, heavier maglev car of mass M2= 44 metric tons and moving at a speed v2= 38.5 mph. Calculate the new speed, V (in m/s), of the system made of the two cars. Assume the collision to be perfectly elastic and neglect all air friction losses.

10.29

15.29

22.94

30.58

Please Explain

Answer 1

$V =\frac{M_{1}v_{1}+M_{2}v_{2}}{ (M_{1}+M_{2})}$

$V =\frac{24.2\times 26.4+44\times 38.5}{ (24.2+44)}= 34.21 mph$

So option 2 is correct.