Answer:
b
c
e
h
Explanation:
Note that the swing direction was not giving in the question and direction could be sideways (in a turn) or in a track or both
The question show something in common ...acceleration
So let's look at the statements and pick the correct ones
a is false while b is correct as the train is accelerating
c is correct. The train is accelerating even thou the speed could not be ascertained
d is false and not feasible as the train is accelerating
e is true as the train maybe moving at a constant speed in a circle
f is false. This could be constant velocity in a circle. Same as g (false)
h is true. It's accelerating
This is false. I hope this helps.
Solution :
Given :
Mass attached to the spring = 4 kg
Mass dropped = 6 kg
Force constant = 100 N/m
Initial amplitude = 2 m
Therefore,
a). 

= 10 m/s
Final velocity, v at equilibrium position, v = 5 m/s
Now, 
A' = amplitude = 1.4142 m
b). 
m' = 2m
Hence, 
c). 

Therefore, factor 
Thus, the energy will change half times as the result of the collision.
The rock strike the water with the speed of 15.78 m/sec.
The speed by which rock hit the water is calculated by the formula
v=
v=
v=15.78 m/sec
Hence, the rock strike the water with the speed of 15.78 m/sec.