Answer:
It will need 20 Watts power to move the box 5 meters in 5 seconds.
Explanation:
The power is defined as the work per unit time or the rate of doing work:
W=dL/dt
Where de work L, can be calculated by multiplying the force by the displacement d:
L=F.d
To this example, F and D are known, therefore the work is:
L=20N . 5m=40 Nm
We know that the work is doing within a time of 5 seconds:
W= 40 Nm / 5s = 20 Nm/s = 20 Watts