Block 1, of mass m1 = 9.30kg , moves along a frictionless air track with speed v
ID: 1282624 • Letter: B
Question
Block 1, of mass m1 = 9.30kg , moves along a frictionless air track with speed v1 = 23.0m/s . It collides with block 2, of mass m2 = 51.0kg , which was initially at rest. The blocks stick together after the collision. (Figure 1)
Part A
Find the magnitude pi of the total initial momentum of the two-block system.
Express your answer numerically.
Part B
Find vf, the magnitude of the final velocity of the two-block system.
Express your answer numerically.
Part C
What is the change ?K=Kfinal?Kinitial in the two-block system's kinetic energy due to the collision?
Express your answer numerically in joules.
pi = kg?m/s Block 1, of mass m1 = 9.30kg , moves along a frictionless air track with speed v1 = 23.0m/s . It collides with block 2, of mass m2 = 51.0kg , which was initially at rest. The blocks stick together after the collision. (Figure 1) Part A Find the magnitude pi of the total initial momentum of the two-block system. Express your answer numerically. Part B Find vf, the magnitude of the final velocity of the two-block system. Express your answer numerically. Part C What is the change ?K=Kfinal?Kinitial in the two-block system's kinetic energy due to the collision? Express your answer numerically in joules.Explanation / Answer
A) Pi = m1*v1 + m2*v2
= 9.3*23 + 0
= 213.9 kg.m/s
B) Pi = Pf
Pi = (m1+m2)*vf
vf = Pi/(m1+m2)
= 213.9/(9.3+51)
= 3.55 m/s
C) delta k = Kf - Ki
= 0.5*(m1+m2)*vf^2 - 0.5*m1*v1^2
= 0.5*(9.3+51)*3.55^2 - 0.5*9.3*23^2
= -2080.5 J