Calculating Final Velocity in a Totally Inelastic Collision

[bmandrade]

Homework Statement

A bigger, moving, vI]i[/I], collides with a smalled train that is not moving. Assume that after the collision the trains stick together. Assume the trains have different masses (m_big and m_small). Write doen the momentum conservation equation for the scenario. Solve for the final velocity of the two trains, v_f

Homework Equations

conservation of momentum
m₁v_1f + m₂v_2f = m₁v_1i + m₂v_2i

The Attempt at a Solution

So i decided that m₁ = m_big and m₂=m_small
m_bigv_{big f} + m_smallv_{small f} = m_bigv_{big i} + m_smallv_{small i}

since v_smalli is at rest then = 0

m_bigv_{big f} + m_smallv_{small f} = m_bigv_{big i}

(m_big+m_small)*v_{bigsmall f} = m_bigv_{big i}

v_{bigsmall f}= m_bigv_{big i}/(m_big+m_small)


is this right??

 

[borgwal]

Correct!

 

[asleight]

Homework Statement

A bigger, moving, vI]i[/I], collides with a smalled train that is not moving. Assume that after the collision the trains stick together. Assume the trains have different masses (m_big and m_small). Write doen the momentum conservation equation for the scenario. Solve for the final velocity of the two trains, v_f

Homework Equations

conservation of momentum
m₁v_1f + m₂v_2f = m₁v_1i + m₂v_2i

The Attempt at a Solution

So i decided that m₁ = m_big and m₂=m_small
m_bigv_{big f} + m_smallv_{small f} = m_bigv_{big i} + m_smallv_{small i}

since v_smalli is at rest then = 0

m_bigv_{big f} + m_smallv_{small f} = m_bigv_{big i}

(m_big+m_small)*v_{bigsmall f} = m_bigv_{big i}

v_{bigsmall f}= m_bigv_{big i}/(m_big+m_small)


is this right??

Looks fine by me.

 

[bmandrade]

ok thanks