# Homework Help: Momentum and Impulse

1. Jan 26, 2005

### kingyof2thejring

Hi there,
i need to know if my approch to this question is right

Particles A, B and C , each of mass m, lie at rest in a straight line in the order stated. A is projected directly towards B with velocity u. The coefficient of restitution is 0.5 in each impact that follows. Show that there will be three impacts in total and find the final velocities of each particle.

working with a and b first
work out momentum before mom = mu +0
and momentum after mom = mv1 + mv2
mu = m(v1 +v2)
u = v1 +v2 {1}

then using the equation velocity of separation = e x velocity of approach
v2-v1 = e(u1-u2)
v2-v1 = 0.5(u-0)
v2-v1 = 0.5u {2}

now adding {1} + {2} > v2=0.75u
v1=0.25u

i would appreciate some advice on my technique/approch to this question

Last edited: Jan 26, 2005
2. Jan 26, 2005

### dextercioby

So how do you define the coefficient of restitution??

Daniel.

P.S.Are u sure u don't need the KE equation??Though i think it is not conserved.

3. Jan 26, 2005