# Help with physics

• Oct 27th 2012, 06:39 AM
Louisana1
Help with physics
A father (m = 94 kg) and son (m = 48 kg) are standing facing each other on a frozen pond. The son pushes on the father and finds himself moving backward at 3 m/s after they have separated. How fast will the father be moving?

Which equation is used to solve this? Can you set up the problem for me?
Thanks
• Oct 27th 2012, 06:42 AM
skeeter
Re: Help with physics
conservation of linear momentum ...

initial momentum = final momentum

$\displaystyle 0 = m_{son}(-3 \, m/s) + m_{father} \cdot v_f$
• Oct 27th 2012, 07:06 AM
Louisana1
Re: Help with physics
what is the final velocity
• Oct 27th 2012, 08:49 AM
skeeter
Re: Help with physics
Quote:

Originally Posted by Louisana1
what is the final velocity

I've set up the equation and you can't figure it out?
• Oct 27th 2012, 11:03 AM
Louisana1
Re: Help with physics
48(-3)+94 x vf
-50 but what is the vf in this problem. I'm still working at it
• Oct 29th 2012, 06:42 PM
Louisana1
Re: Help with physics
-48(-3)/94=1.53 m/s
thx