Question

What is the net displacement of the wedge when the ball reaches the bottom of the groove.

• A. $\frac{mR}{M+m}$ to the left
• B. $\frac{mR}{M+m}$ to the right
• C. $\frac{m(R-r)}{M+m}$ to the left
• D. $\frac{m(R-r)}{M+m}$ to the right

Answer 1

The correct option is C $\frac{m(R-r)}{M+m}$ to the left

$\Delta x_{CM}=\frac{Mx+m(R-r+x)}{M+m}$
$0=Mx+mx+m(R-r)$
$x=\frac{-m(R-r)}{M+m}$