Answer:
0.184 m/s
Step-by-step explanation:
Momentum is conserved. If the velocity of the 0.24 kg mass is positive, then ...
m1v1+m2v2 = m3v3
(0.24 kg)(0.60 m/s) +(0.26 kg)(-0.20 m/s) = (0.24 +0.26 kg)(v)
v = (0.144 -0.052 kg·m/s)/(0.50 kg) = 0.184 m/s
The speed of the combined masses is 0.184 m/s.
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Additional comment
The positive sign indicates the combined masses are moving in the direction of the original 0.24 kg mass.