A particle is given an initial speed `u` inside a smooth spherical shell of radius `R=1` m such that it is just able to complete the circle. Acceleration of the particle when its velocity is vertical is

Options

A. `gsqrt(10)`
B. `g`
C. `gsqrt(2)`
D. `gsqrt(6)`

Answer

A

Explanation

Loss in KE = gains in GPE
`implies 1/2 m (sqrt5 gR)^(2) - 1/2 mv^2 = mgR " " implies " " v = sqrt(3 gR)`
`N = (mv^2)/R = 3 mg implies a_r = 3g and a_t = g implies a_("net") = sqrt(10)g`