A series circuit has only one path for current,
while a parallel circuit has more than one.
Answer:
t=2s
Explanation:
The definition of power is:

And the work-energy theorem states that:

Since the movement starts from rest, we have that:

And putting all together:

Since we want the time taken:

Which for our values is:

The formula for acceleration is the velocity times the inverse of time so it would be 21 times 1/13. So roughly 0.0769... is the acceleration(m/s^2).