A tunnel is dug along a chord of Earth having length `sqrt(3)R` is radius of Earth. A small block is released in the tunnel from the surfasce of Earth. The particle comes to rest at the centre of tunnel. Find coefficient of friction between the block and the surface of tunnel. Ignore the effect of rotation of Earth.

A tunnel is dug along a chord of non rotating earth at a distance d=(R)/(2) [R = radius of the earth] from its centre. A small block is released in the tunnel from the surface of the arth. The block comes to rest at the centre (C) of the tunnel. Assume that the friction coefficient between the block and the tunnel wall remains constant at mu. Calculate work done by the friction on the block. Calculate mu.

A tunnel is dug along a diameter of the earth. Find the force on a particle of mass m placed in the tunnel at a distance x from the centre.

A tunnel is dug along a diameter of the earth. Find the force on a particle of mass m placed in the tunnel at a distance x from the centre.

A tunnel is dug along a diameter of the earth. Find the force on a particle of mass m placed in the tunnel at a distance x from the centre.

A smooth tunnel is dug along the radius of the earth that ends at the centre. A ball is released from the surface of earth along the tunnel. If the coefficient of restitution is 0.2 between the surface and ball, then the distance travelled by the ball before second collision at the centre is