Physics Question

[AgaBoogaBoo]

A 50g projectile is launched with a horizontal velocity of 647 m/s from a 4.65kg launcher moving in the same direction at 2.00 m/s. What is the velocity of the launcher after the projectile is launched?

We have two equations, elastic and inelastic. I think it would be elastic because they are seperated.

Answer is 4.94 m/s

 

[Chronoshock]

IT'S TOO LATE!!! FINALLS ARE OVAAAAAAHHHHHHHHHHH

 

[MSCoder610]

Sounds easy enough.
Initial Momentum = Final Momentum
(Initial Mass)(Initial Velocity) = M1V1 + M2V2 (since they are together first, but then split)

(0.05+4.65 kg) (2 m/s) = 0.05 kg (647 m/s) + 4.65 kg (X m/s)
Solve for X, you should get -4.94.
The negative means that the launcher is moving in the opposite direction now (as the projectile).

Normally, I think unless the problem specifically states that the collision is elastic, you can't use that it is.

 

[AgaBoogaBoo]

Thanks!

 

[orakle]

Originally posted by: MSCoder610
Normally, I think unless the problem specifically states that the collision is elastic, you can't use that it is.

my teacher told me that too. never assume the collision is elastic unless the problem specifically tells you it is