Posted by Megan on .
Ann, a 66.1 kg person throws a 0.0460 kg snowball forward with a ground speed of 31.7 m/s. Billy, with a mass of 60.5 kg, catches the snowball. Both people are on skates. Ann is initially moving forward with a speed of 2.29 m/s, and Billy is initially at rest. After the snowball is exchanged (a) What is Ann’s velocity? (b) What is Billy’s velocity? Disregard friction between the skates and the ice.

Physics 
Elena,
m1=66.1 kg, v1=2.29 m/s
m2=0.046 kg, v2= 31.7 m/s
m3=60.5 kg, v3=0
u1=? u3=?
The law of conservation of linear momentum
(m1+m2) •v1 =m1•u1 +m2•v2
u1= [(m1+m2) •v1 m2•v2]/m1 =
=[(66.1+0.046) •2.29 – 0.046•31.7]/66.1 = 2.269 m/s
m2•v2=(m2+m3) •u3
u3= m2•v2/(m2+m3) =
=0.046•31.7/(0.046+60.5)=0.024 m/s 
Physics 
Ana,
I got the correct answer for the thrower, but for the catcher to find the second velocity, I follow the formula but it still counts it as wrong. What could I be doing wrong?