The diagram shows a ballistic pendulum,used to measure the speed of the bullets.The 3,235kg wooden block hangs from a 3m cord.When a bullet is fired into it from close range ,it swings through an angle of 18 before coming to rest ,and is afterwards found to have a mass of 3,250kg.calculate:

Question

The diagram shows a ballistic pendulum,used to measure the speed of the bullets.The 3,235kg wooden block hangs from a 3m cord.When a bullet is fired into it from close range ,it swings through an angle of 18 before coming to rest ,and is afterwards found to have a mass of 3,250kg.calculate:
(a)the speed of the bullet
(b)the kinetic energy of a bullet as it left the gun barrel

bobpursley · Answer

determine the height the bullet/block went up.
calculate the PE it has there
then that is the KE it has just after the bullet hits it.
calcuate the momentum it had when it started swinging from that.
consrvation of momentum applies: that has to equal the momenum of the bullet just before impace. Now calculte the bullet spleed from this.