Suppose a tunnel could be dug through the Earth from one side to the other along a diameter, as shown in Fig. 14-10. A p

[answerhappygod]

Suppose a tunnel could be dug
through the Earth from one side to the other along a diameter,
as
shown in Fig. 14-10. A particle of mass m is dropped into the
tunnel
from rest at the surface. (a) What is the force on the
particle
when it is a distance r from the center? (b) What is the speed
of
the particle when it is a distance r from the center? Evaluate
the
speed at r   0. Neglect all frictional forces and assume that
the
Earth has a uniform density.