1.

A frequently used device to measure the speed of bullets is the ballistic pendulum. It comprises of a heavy block of wood of mass M suspended by two long chords. A bullet of mass m is fired into the block horizontally. The block, with the bullet embedded in it, swings upwards. The centre of mass of the combination rises through a vertical distance h before coming to rest momentarily. In a particular experiment, a bullet of mass 40 gm is fired into a wooden block of mass 10 kg. The block is observed to rise by a height of 20.0 cm.Fraction of initial energy lost in the collision

Answer»

`0.9880`
`0.9960`
`0.9040`
`0.9755`

SOLUTION :Final `K.E.=(1)/(2)(M+m)v^(2)=(1)/(2)(M+m)(2gh)=20.08 J`
Initial `K.E. = (1)/(2)m U^(2)=(1)/(2)xx(40)/(1000)xx502^(2)=5040.08 J`
Fractional loss of K.E. = 0.9960
`therefore` (B)


Discussion

No Comment Found

Related InterviewSolutions