A bead of mass m and diameter d is sliding back and forth with velocity v on a wire held between two right walls of length L. Assume that th ecollisions with the wall are perfectly elastic and ther is no friction. The average force that the bouncing bead exerts on the one of the walls is :_

Options

A. `(mv^(2))/(L - d)`
B. `(mv^(2))/(L + d)`
C. `(2mv^(2))/(L - d)`
D. `(2 mv^(2))/(L + d)`

Answer

A

Explanation

`Deltap =` change in momentum `= 2mv`
`Deltat =` time between two collsion `(2(L - d))/(v)`
`:.` Force exerted on wall
`= (Deltap)/(Deltat) = (mv^(2))/((L - d))`