Question

A blue cylinder and a green cylinder are on a horizontal turntable that is spinning counter-clockwise as seen from above.
A blue cylinder and the green cylinder are identical most every respect expect for their colors and masses(The blue one is taller to give it more mass). The blue cylinder is twice as massive as the green cylinder.
The cylinder are located the same distance from the center of the turntable, as pictured below. When the turntable spin fast enough, the green mass slides off. How many times as fast(compared to the speed at which the green mass slides off) must the turntable spin to cause the blue mass to slide off?

• A. The blue mass will slide off at the same speed as the green one will.
• B. 2 times as fast
• C. 3 times as fast
• D. 4 times as fast
• E. The blue mass will slide off at a slower

Answer 1

The correct option is A The blue mass will slide off at the same speed as the green one will.

For the sliding away of a mass from the turntable, the maximum static frictional force acting on mass must be lesser than the centrifugal force on it.

Hence at the critical point,

$\frac{m{v}^2}{R}=\mu mg$

$⟹v=\sqrt{\mu gR}$

Hence the speed is same for both the cylinders.