A bullet of mass M is fired with a velocity 50 m/s at an angle with the horizontal. At the highest point of its trajectory, it collides head-on with a bob of mass 3M suspended by a massless string of length 10/3 metres and gets embedded in the bob. After the collision, the string moves through an angle of 120∘ . Find
a. the angle θ
b. the vertical and horizontal coordinates of the initial position of the bob with respect to the point of firing of the bullet. Take g=10 m/s2