When a 2 kg car driven at 20 m/s on a level road is suddenly put into neutral gear (i.e. allowed to coast), the velocity decreases in the following manner:  

$V=\frac{20}{1+\left(\frac{t}{20}\right)}m/s$  where t is the time in sec. The power (in Watt) required to drive this car at speed 10 m/s on the same road is