Answer:
C) if they are based on a very small sample
Part A)
As we know that spring force is given by
F = kx
here x = stretch in the spring from natural length
So here when spring reaches to its natural length
Force due to spring = 0
so acceleration = 0
Part b)
When spring is compressed from its natural length it will have elastic potential energy in it
so it is given by

now we know that there is no friction in it so maximum kinetic energy of the launcher must be equal to the elastic potential energy of the spring

here we have
k = 70 N/m
x = 0.4 m


Part c)
Now to find the speed we know that



so its speed is 6.11 m/s
Answer:
The value is
Explanation:
From the question we are that
The velocity 
The time taken is
The total mass of the train is 
Generally the average power delivered is mathematically represented as
=>
=>