Answer:
[tex]mg +\frac{mv^{2}}{r}[/tex]
Explanation:
At the bottom of the pipe :
[tex]N[/tex] = Normal force acting in upward direction
[tex]m[/tex] = mass of the ball
[tex]W[/tex] = weight of the ball acting in downward direction = mg
[tex]v[/tex] = speed of the ball at the bottom
[tex]r[/tex] = radius of curvature
Force equation for the motion of ball is given as
[tex]N - W = \frac{mv^{2}}{r}[/tex]
[tex]N - mg = \frac{mv^{2}}{r}[/tex]
[tex]N = mg +\frac{mv^{2}}{r}[/tex]