In order to determine the acceleration of the block, use the following formula:

Moreover, remind that for an object attached to a spring the magnitude of the force acting over a mass is given by:

Then, you have:

by solving for a, you obtain:

In this case, you have:
k: spring constant = 100N/m
m: mass of the block = 200g = 0.2kg
x: distance related to the equilibrium position = 14cm - 12cm = 2cm = 0.02m
Replace the previous values of the parameters into the expression for a:

Hence, the acceleration of the block is 10 m/s^2
Answer:
10000 J or 10 KJ
Explanation:
power = workdone/time taken
400 = workdone/25
workdone = 400 * 25
=10000 J
Friction? For example, like when a car's tires skid on rough concrete.