A solid sphere rolls without slipping, first horizontal and then up to a point X at height h on an inclined plane before rolling down, as shown.

The initial horizontal speed of the sphere is

Options

A. `sqrt((10gh)/(7))`
B. `sqrt((7gh)/(5))`
C. `sqrt((5gh)/(7))`
D. `sqrt(2gh)`

Answer

A

Explanation

`mgh=(1)/(2)mv^(2)+(1)/(2)(2)/(5)mR^(2)(v^(2))/(R^(2))impliesmgh=(7)/(10)mv^(2)`
`impliesv=sqrt((10gh)/(7))`.