Vector components with i-hat and j-hat in collision problems

[jperez94]

Hey there, I'm lost with this one:

Two 3-kg masses have velocities v(1)= 2m/s i-hat plus 3m/s j-hat and v(2)= 4m/s i-hat minus 6m/s j-hat. Find the velocity of the center of mass of the system.

Now, I know how to go about calculating the velocity of the center of mass (v(cm)= m(1)V(1)+m(2)V(2)/m(1)+m(2)

The thing that throws me off is the j-hats and i-hats. How do I come out with a vector number? I thought of the pothagarem(sp?) therom, but decided that couldn't work. Any ideas? Thanks.

 

[himanshu121]

u mean pythagoras Theorem , it should work

 

[HallsofIvy]

Treat "i-hat" and "j-hat" as two separate problems. Then put them back together into the "momentum vector" with i and j components.