Assuming a constant angular acceleration....?

Question

what torque would superman need to exert on the Earth to stop it from spinning in 1 hour?

Answer 1

Torque T
T=I(alpha)
I - moment of inertia of the Earth
alpha – angular acceleration

I= (2/5) m R^2
m- mass of the Earth
R - Radius of the earth

The angular velocity of the Earth = omega
omega= (2 pi/R) (1 rev /day)/(24 x 3600)

alpha = change in omega/time
alpha = omega/3600 sec

Finally

T= 2 pi (2/5) m R^2 (1/R) (1 rev /day)/(24 x (3600)^2)
T= (4/5) pi m R/(24 x (3600)^2)
R=Mean radius: 6,372.797 km
m=5.9736 E24 kg
T=306 E+21 meter-Newtons