# Wedge- Block Problem

## Homework Statement

A block of mass m is placed on a triangular block of mass M which in turn is placed on a horizontal surface. Assuming friction less surfaces find the velocity of the triangular block when the smaller block reaches the bottom end.The angle of inclination of the plane is 'theta'.

## The Attempt at a Solution

my approach to the problem........

when the small block reaches the bottom......momentum in x direction is conserved....

mu=Mv....where u and v are absolute velocities of the smallerb block bigger block respectively

applying conservation of energy.....mgh=1/2mu(squared)+1/2mV(squared)

solving the above two equations.....

V=m/M(root of){2Mgh/M+m}

but the answer is complex in terms of angle.....please explain where I am wrong

ehild
Homework Helper

## Homework Statement

A block of mass m is placed on a triangular block of mass M which in turn is placed on a horizontal surface. Assuming friction less surfaces find the velocity of the triangular block when the smaller block reaches the bottom end.The angle of inclination of the plane is 'theta'.

## The Attempt at a Solution

my approach to the problem........

when the small block reaches the bottom......momentum in x direction is conserved....

mu=Mv....where u and v are absolute velocities of the smallerb block bigger block respectively

applying conservation of energy.....mgh=1/2mu(squared)+1/2mV(squared)

solving the above two equations.....

V=m/M(root of){2Mgh/M+m}

but the answer is complex in terms of angle.....please explain where I am wrong

I do not see the angle in your derivation. What exactly is your u?