Hi everyone!
I just don't get part b), please help!
The Earth may be considered to be a uniform sphere of radius 6380 km with its mass of 5.98 × 1024 kg concentrated at its centre.
A mass of 1.00 kg on the Equator rotates about the axis of the Earth with a period of 8.62 × 104 s.
(a) Calculate, to three significant figures,
i) the gravitational force FG of attraction between the mass and the Earth,
=9.80 N
ii) the centripetal force FC on the 1.00 kg mass,
=0.0339 N
iii) the difference in magnitude of the forces.
=FG – FC = 9.77 N
Now what I don't get is why FG and FC are not added for part b). Don't both forces act in the same direction?
b) By reference to your answers in (a), suggest, with a reason, a value for the acceleration of free fall at the Equator.
=9.77 ms-2
Any help appreciated!