# Problem with equation / proving formula

1. Apr 25, 2016

### Trec93

1. The problem statement, all variables and given/known data
I have to prove some formula, I got stuck in the process.

2. Relevant equations
Formula to prove:
$$v_{0} = \frac{M+m}{m}\sqrt{2gus}$$
Valid equation that should get me to this formula:
$$\frac{m^2v_{0}^2}{2(M+m)} = gmus$$

3. The attempt at a solution
$$v_{0}^2=\frac{2(M+m)}{m^2}gmus$$
$$v_{0}^2 = \frac{M+m}{m}2gus$$
$$v_{0} = \sqrt{\frac{M+m}{m}2gus}$$

I'm pretty sure my math has failed me here, that right handside of the equation seems fishy, or maybe book did a mistake?

Last edited: Apr 25, 2016
2. Apr 25, 2016

### Let'sthink

You seem to be correct may be there is a mistake in the book, what is u?

3. Apr 25, 2016

### Trec93

Yeah I'm probably gonna assume that there's a mistake in the book, u is the coefficient of friction, this equation is the given equation of kinetic energy = work where the force is the force of friction.