Taylor mechanics chap3,problem 4

[kylinsky]

Homework Statement

two man,each of equal mass m,are standing at one end of a stationary railroad flatcar with frictionless wheel and mass m_car.Find the car's speed if the two men run to the other end of the car and jump off simultaneously with the same speed u(relative to the car)

Homework Equations

The Attempt at a Solution

let v_h be the men's speed relative to the ground at the instant they jump off the car.Thus
u= v_h+v_car.Since the momentum of the system is conservative,2mv_h=m_carv_car

After solving the equations,i got (2mu)/(2m+m_car) ,but i found a different answer from mine on the website http://chriskranenberg.wix.com/taylor-mechanics-solutions.I want to make sure which one is right[/B]

 

[gneill]

Homework Statement

two man,each of mass [m][/h],are standing at one end of a stationary railroad flatcar with frictionless wheel and mass [m][/fc].Find the car's speed if the two men run to the other end of the car and jump off simultaneously with the same speed u(relative to the car)

Homework Equations

The Attempt at a Solution

i got (2[m][/h]u)/(2[m][/h]+[m][/fc]) ,but i found a different answer from mine on the website http://chriskranenberg.wix.com/taylor-mechanics-solutions.I want to make sure which one is right[/B]

Your notation is strange. What is, for example, [m][/h] meant to convey?

You'll need to show the details of your own solution, how you arrived at your result. Helpers won't just confirm or deny a given solution for you.