during a snowball fight two balls with masses of 0.28 and 0.75 kg, respectively , are thrown in such a manner that they meet head-on and combine to form a single mass. the magnitude of initial velocity for each is 15 m/s. what is the speed of the combined mass immediately after collision?

Answer 1

m1v1 + m2v2 = (m1+m2)vf
And watch your directions, one must be negative.