Answer:
Explanation:
Given
mass of each railroad is M
first railroad is moving with velocity
and other two's with 
conserving Momentum

where v_f is the final velocity of combined system
(b)Initial Kinetic Energy


Final Kinetic Energy

Loss in Kinetic Energy


Answer:
Please see below as the answer is self- explanatory.
Explanation:
- Any time that an object changes direction (from leftward to rightwward, or from upward to downward) the velocity must be zero just for one instant, when is on the verge of changing the direction.
- This is needed because velocity changes as a continuous function of time, so it needs to cross the t-axis when passing from positive to negative or vice versa.
- However, the claim that in the moment that velocity is zero, the acceleration is also zero, is false.
- Due to acceleration is the rate of change of velocity, and velocity is a vector, this means at any time there is a change of direction, there is an acceleration that is non-zero.
- For example, when an object that has been thrown upward, reaches to its maximum height, just one instant before starting to fall, the velocity becomes zero, but the acceleration (which causes the object to fall) is non-zero, due to it's the acceleration due to gravity.
Link provided in other answer is a SCAM, don’t click on the link !!!!
6,5 6,4 6,3 6,2 6
if you know,1
B would be the correct answer