Answer:8.69 m/s
Explanation:
Given
mass of Empty train 
velocity of car 
mass of Boulder 
Since no External force is acting therefore conserving Momentum
Train and boulder moves with same velocity after collision



The answer is C) a rolling bowling ball because kinetic energy is the energy of movement and potential energy is the energies of the others, since there are not in movement. i hope this helps.
Answer:
D. 2^(3/2)
Explanation:
Given that
T² = A³
Let the mean distance between the sun and planet Y be x
Therefore,
T(Y)² = x³
T(Y) = x^(3/2)
Let the mean distance between the sun and planet X be x/2
Therefore,
T(Y)² = (x/2)³
T(Y) = (x/2)^(3/2)
The factor of increase from planet X to planet Y is:
T(Y) / T(X) = x^(3/2) / (x/2)^(3/2)
T(Y) / T(X) = (2)^(3/2)