COMEDK2023Morning ShiftPhysicsCenter of Mass, Momentum and CollisionActual
In the figure, pendulum bob on left side is pulled a side to a height h from its initial position. After it is released it collides with the right pendulum bob at rest, which is of same mass. After the collision, the two bobs stick together and rise to a height
Options
- A2 h 3
- Bh 4
- C3 h 4
- Dh 2
Correct answer
B. h 4
Step-by-step solution
Let m be the mass of each pendulum bob and L be the length of the strings. When the left bob is released from height h , its velocity v just before the collision is found using the conservation of mechanical energy: 1 2 mv^2 = mgh v = 2gh The collision is perfectly inelastic because the two bobs stick together. Let V be the velocity of the combined mass 2m immediately after the collision. By the principle of conservation of linear momentum: mv + m(0) = (m + m)V mv = 2mV V = v 2 = 2gh 2 After the collision, the comb