Physic C....linear momentum!!!!!!?

Question

A 4.0 kg mess kit sliding on a frictionless surface explodes into two 2.0 kg parts: 3.0 m/s, due north, and 5.0 m/s, 30° north of east. What is the original speed of the mess kit?

Answer 1

Px = 2*5*cos30° = 8.66 kg∙m/s

Py = 2(3 + 5*sin30°) = 11 kg∙m/s

Ptot = √(Px²+Py²) = 14 kg∙m/s

Vo = Ptot/Mtot = 14/4 = 3.5 m/s

Answer 2

ok. its not to bad.

draw the picture first and it will make more sense. look at what you have to find exactly and go from there.

in the x direction you will use cosine and the y sine so you have

Px = 2(5)cos30 = 8.66

Py = 2(3 + 5sin30) = 11

find magnitude

Ptotal = sqrt(Px²+Py²) = 14

remember p=mv so rearrange the equation.

Vi = Ptotal/Mtotal = 14/4 = 3.5 m/s  

i hope that makes sense.. im pretty sure its right