- #1

- 1,041

- 3

## Homework Statement

A bullet of mass m is fired with a velocity of 50m/s at an angle x. At the top of its trajectory it hits a bob of mass 3m hanging by a string 3.3 m long and gets imbedded in it. The string rotates by an angle of 120 degrees.

Find x and the coordinates of the bob wrt the projectile.

## The Attempt at a Solution

The bullet hits the bob with velocite 50 cosx. The kinetic energy of the bullet gets converted into the gravitational potential energy of the bob and the bullet.

[tex]0.5m(50cosx)^2= 4mg*3.3*(1+sin30)[/tex]

cosx=0.4

The answer, however, is 30 degrees. I used cosx=0.4 to solve the second part, but needless to say, that answer didnt match either.

What did I do wrong? Or is the given answer incorrect?