A solid ball of mass m and radius r rolls without slipping through a loop of radius R, as shown in the figure. From what height h should the ball be launched in order to make it through the loop without falling off the track?

THINK:
Determine the height
should the ball be launched in order to make it through the loop without falling off the track.
SKETCH:
The figure shows a solid ball of mass
and radius
is rolling without slipping through a loop of radius
.
RESEARCH:
Energy is conserved because there is no friction and slipping. The only force acting on the ball at the top of the loop is the centripetal force, and is given by
SIMPLIFY:
The initial potential energy of the ball, 
The initial kinetic energy of the ball,
The final potential energy of the ball at the top of the loop, 
The final kinetic energy of the ball at the top of the loop is,

Here,
for the solid sphere.
CALCULATE:
According to the law of conservation of energy, the initial energy of the system is equal to the final energy of the system. Then,

