chapter  26
6 Pages

Linear momentum and impulse

Mass m1 = 10 t = 10,000 kg, m2 = 15,000 kg and velocity u1 = 6 m/s, u2 = 0 Total momentum before impact

= m1u1 + m2u2 = (10,000 × 6) + (15,000 × 0) = 60,000 kg m/s.

Let the common velocity of the wagons after impact be v m/s. Since total momentum before impact = total momentum after impact:

60,000 = m1v + m2v = v(m1 + m2) = v(25,000)

Hence, v = 60,000 25,000

= 2.4 m/s

i.e. the common velocity after impact is 2.4 m/s in the direction in which the 10 t wagon is initially travelling.