- #1

Nerrad

- 20

- 0

## Homework Statement

A small spherical rock of mass collides in space with a large spherical rock of mass as indicated in the diagram. After the collision the rocks stick together to form a single spherical object.

https://postimg.org/image/fltmg3bj5/

(New here so I've no clue how to upload photo) https://postimg.org/image/fltmg3bj5/

Note: I only need help with Question d)

Consider the frame of reference in which the large rock is initially stationary and the small rock is moving with velocity as shown. You may assume that |v| ≪ c.

a) Explain in words what happens when the two rocks collide with the condition a = 0 and also what happens in the case that is not equal to zero.

b) If a= 0.0m , R= 1 m, m= 1kg , M = 10000 and |v| = 100m /s , calculate the velocity of the object after the collision.

c) If a= 0.5 m calculate the velocity of the object after the collision and comment on your result.

d) For c) calculate the total angular momentum about of the system and hence the rotation rate of the object after the collision. You may assume that the change in radius is negligible after the collision and use the approximation m≪M . [Hint. The moment of inertia of a sphere is 2/5 MR^2 .]

## Homework Equations

## The Attempt at a Solution

From the previous questions I found out that the linear velocity of the rock to be 0.01m/s. So I used v=Rw to find the angular velocity and then use (Angular Momentum equation) L = Iw and using I as (2/5)MR^2. I got 40kgm^2/s but the answer says it is 50 kgm/s^2 and the angular velocity is 0.0125rad/s. What have I done wrong?