Homework Help: physics

Posted by dave on Thursday, September 2, 2010 at 11:33am.

at on time, the velocity of a rifle bullet was measured using a ballistic pendulum made up of a wooden block suspended from a string. the block used here has a mass of 20kg. a 50g rifle bullet is fired into the block, penetrating it by 10cm and causing it to swing upwards, increasing its height by 20cm.

a) calculate the velocity of the bullet as it enters the wooden block. Express you answer in km/h.

b) calculate the frictional force between the bullet and the wooden block.

physics - bobpursley, Thursday, September 2, 2010 at 11:51am
Use conservation of energy (GPE=KEinitial) to find the velocity of the block/bullet at impact. Then, use conservation of momentum to find the initial velocity of the bullet at impact.

the work done by the bullet can be determined by energy:

KE of block/bullet-friction*.10m=KE bullet initial.

Answer this Question

Related Questions

physics - A ballistic pendulum consists of a rectangular wooden block of mass 1....
Physics - A rifle with a mass of 1.2 kg fires a bullet with a mass of 6.0 (0....
Physics - A bullet of mass 3.2 g strikes a ballistic pendulum of mass 3.6 kg. ...
physics - A bullet of mass 8 g strikes a ballistic pendulum of mass 2.0 kg. The ...
Physics - A rifle has a mass of 4.73 kg and it fires a bullet of mass 13.6 g at ...
physics - You are hired as ballistics expert and need to measure the muzzle ...
Physics - A bullet of mass 4.8 g strikes a ballistic pendulum of mass 3.3 kg. ...
physics - The ballistic pendulum is a device used to measure the speed of a fast...
Physics - A ballistic pendulum was a device used in the past century to measure ...
physics - A ballistic pendulum, as shown in the figure, was a device used in the...

For Further Reading

First Name:
School Subject:
Answer: