- #1
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Homework Statement
In a physics lab, 0.30 kg puck A, moving at 5.0 m/s [W], undergoes a collision with a 0.40 kg puck B, which is initially at rest. Puck A moves at 4.2 m/s [W 30 N] . Find the final velocity of puck B.
Homework Equations
Conservation of momentum
Pythagorean theorum
The Attempt at a Solution
[/B]
I understand the steps I need to take to solve this question but once again I am getting a different answer than what I find online. Any help on where I went wrong would be great.
Let north and east be positive.
My diagram of the x and y components
https://i.imgur.com/0F5MsrP.png
Using conservation of momentum for the components
X-components:
(Not sure if all of the subscripts are correct in this part)
m1v1ox+m2v2ox=m1v2fx+m2v2fx
(0.30)(-5)+(0.40)(0)=(0.30)(-3.64)+(0.40)v2fx
-1.5=-0.692
v2fx=-0.808
The answer online for this was -1.0. Was it just rounded down or did I go wrong somewhere?
For the y-component:
m1v1oy+m2v2oy=m2v1fy+m2v2fy
(0.30)(0)+(0.40)(0)=(0.30)(2.1)+(0.40)v2fy
0=1.03
v2fy=1.03
The answer online for this was -1.6, so I went wrong here too?
I didn't go beyond this part because I think my answers are wrong. I know that next I create a triangle with my answers and use pythagoreans theorem to solve for the missing side, then I use tan to find the direction and I have the final velocity with it's direction.
Also I haven't learned this yet but does the "o" in "v1o" mean initial? Does the "f" in v1f mean final?