Answer:
Power = Work / Time
P = 400 kg * 9.8 m/s * 4.5 m / 3600 sec = 4.9 J/s = 4.9 Watts
Also, 4.9 Watts / (746 Watts / Horsepower) = .0066 Hp
speed of tortoise is given as v1 = 0.14 m/s
speed of hare is given as v2 = 20*0.14 = 2.8 m/s
now let say the total length of the path is "d"
so the total time taken by the tortoise to cover this

now given that hare took rest for 1 min
so total time of run for hare is (t - 60)s
so the distance that hare covered is given by

now by above two equations



and the time t is given by


so part a)
t = 63 s
part b)
d = 8.82 m
Explanation:
The Coulomb's law states that the magnitude of each of the electric forces between two point-at-rest charges is directly proportional to the product of the magnitude of both charges and inversely proportional to the square of the distance that separates them:

In this case we have an electron (-e) and a proton (e), so:

In this case, the electric force is negative, therefore, the force is repulsive and its magnitude is:

Centripetal force = (mass) x (speed)² / (radius)
= (20 kg) x (20 m/s)² / (20 m)
= (20 x 20 / 20) (kg-meter/sec²)
= 20 newtons