When a train first starts going down the railroad, it is very difficult for it to get going. When it comes to a stop, it has a hard time slowing down. Why is this?

A: balanced forces

B: unbalanced forces

C: inertia

The option (c) is correct

Explanation:

When we apply the force on any body, the inertia comes into play. It is the tenancy of the the body to oppose the force which tends to change its state.

In first case the train tries to change its state from rest to motion. Thus the inertia of rest opposes this tendency.

In the second case, the train tries to come from motion to the state of rest. Thus again, inertia opposes it.

Therefore inertia is the factor which creates difficulty in both case. Hence option (c) is correct