The sound bounces from wall to wall, so you draw arrows down the length of the canyon in both directions.
answer
the final velocity is half of train car B's initial velocity
explanation
the conservation of momentum states that the initial and final total momentum are equal
m1v1 + m2v2 for initial momentum
(m1 + m2)v3 for final momentum because both cars stick together so their masses are combined
m1v1 + m2v2 = (m1 + m2)v3
since the mass of both are the same, m1 = m2
m1v1 + m1v2 = (m1 + m1)v3
m1(v1 + v2) = 2m1v3
divide both sides by m1
v1 + v2 = 2v3
since train car A is initially at rest, v1 = 0
v2 = 2v3
v3 = v2 * 1/2
the final velocity is half of train car B's initial velocity
Answer:
The work done by friction was 
Explanation:
Given that,
Mass of car = 1000 kg
Initial speed of car =108 km/h =30 m/s
When the car is stop by brakes.
Then, final speed of car will be zero.
We need to calculate the work done by friction
Using formula of work done



Put the value of m and v



Hence, The work done by friction was 