An object that's moving doesn't necessarily change its speed or acceleration. Also, the force applied to it doesn't need to change ... in fact, a moving object doesn't need ANY force applied to it in order to keep moving.
But any moving object WILL have a change in its position ... THAT's how you know it's moving, and that's WHY you say "It's moving !". (choice-B)
Answer:

Explanation:
From the conservation of mechanical energy




Solve to velocity v2




600 watts may be your answer:)
Part a)
At t = 0 the position of the object is given as

At t = 2

so displacement of the object is given as

so average speed is given as

Part b)
instantaneous speed is given by


now at t= 0

at t = 1


at t = 2

Part c)
Average acceleration is given as



Part d)
Now for instantaneous acceleration
As we know that

at t = 0

at t = 1

now we have

At t = 2 we have



<em>so above is the instantaneous accelerations</em>