 #1
 208
 36
 Homework Statement:

A thin rod of mass M and length L is struck at one end by a ball of clay of mass m, moving with speed v as shown in figure. The ball sticks to the rod. After the collision, the angular momentum of the clayrod system about A, the midpoint of the rod, is
a. (m + M/3)(vL/2)
b. (m + M/12)(vL/2)
c. (m + M/6)(vL/2)
d. mvL/2
e. mvL
Answer: D
 Relevant Equations:
 Angular Momentum = I W
I calculate in this way :
Angular Momentum = I W
= [ ( 1/12 ML^2 + m(L/2)^2 ] (V/ L/2)
= [ 1/12 ML^2 + 1/4 mL^2 ] 2V/L
= 2VL/4 [ M/3 + M]
but can not find a matching answer. Why?
Angular Momentum = I W
= [ ( 1/12 ML^2 + m(L/2)^2 ] (V/ L/2)
= [ 1/12 ML^2 + 1/4 mL^2 ] 2V/L
= 2VL/4 [ M/3 + M]
but can not find a matching answer. Why?