Conservation of Momentum: Inelastic Collisions

Posted by: Anonymous

Conservation of Momentum: Inelastic Collisions - 11/09/04 03:53 AM

My daughter is learning about mass, velocity and momentum... The teacher has only given partial instructions, and I'm not sure I have the correct answer.
Formulas given: v=velocity, m=mass, p=momentum
v=p/m, m=p/v, p=vm
This is the problem:
Truck 1 (mass = 2500kg and velocity = 30m/s) hits Truck 2 (mass = 1500kg and velocity = 0m/s). Truck 1 and Truck 2 lock together. What is the final speed of both trucks?
My guess at the solution is:
T1: m=2500kg, v=30m/s, so p=2500kg*30m/s=75000kgm/s
When it hits Truck 2, and the two trucks lock together, you combine the mass:
(T1)2500kg + (T2)1500kg = (T1+T2)4000kg
and divide the momentum (75000kgm/s) by the combined mass (4000kg), coming up with the combined velocity of 18.75m/s.
Is this correct?
Posted by: Steerpike

Re: Conservation of Momentum: Inelastic Collisions - 11/09/04 12:39 PM

Looks OK to me - keep Smiling!