Answer:
767.6 m/s
Explanation:
We consider momentum in both x and y components
Since momentum, p=mv where m denote mass while v is velocity then
In the y direction
3m*288=279m+my
y=585 m/s
In the x direction and taking right as positive then
3m*288=367m+mx
x=497 m/s
The resultant gives the velocity of the third fragment
[tex]Third=\sqrt{585^{2}+497^{2}}=767.6157893\approx 767.6 m/s[/tex]