Answer:
The time-interval of the collision is 
Explanation:
As given the force is equal to the rate of change of momentum. Mathemticaly this is:

We can rearrange this equation to solve for
which gives
which is our answer.
In words this means the time interval is equal to the momentum change in that interval divided by the force applied that caused this momentum change.
B. Conductors allow electricity to go through them only. Such as copper etc.
To lift heavy objects it it main function