Four billiards balls, each of mass 0.5 kg, all are travelling in the same direction on a billiard table, with speeds of 2 m/s, 4 m/s, 8 m/s and 10 m/s. What is the linear momentum of this system?
12 kg-m/s
The linear momentum of a system is simply the sum of the linear momentum of the constituent parts. Thus we only need to find the momentum of each ball :
P = m1v1 + m2v2 + m3v3 + m4v4 = 1+2+4+5 = 12
Thus the total momentum of the system is 12 kg-m/s.