Question

The pendulum bobs in the figure are made of soft clay so that they stick together after impact. The mass of bob B is 14 times that of bob A. Bob B is initially at rest. If bob A is released from a height h above its lowest point, what is the maximum height attained by bobs A and B after the collision?


I also don't have any clue about this one! Please help, thanks.

Answer 1

Here's two or three clues.

For the velocity of A just before impact (Va), use conservation of energy.

g*h = (1/2)*Va^2

For the velocity of and b stuck together after impact (Vfinal) , use conservation of momentum. (It is not an elastic collision)
Ma*Va = Vfinal*(Ma + Mb)
= 15*Ma*Vfinal

Once you get Vfinal, use conservation of energy again to get the height that they rise together.

Answer 2

Thanks!

Answer 3

Thank you Drwls :)