# Ballistic pendulum ~help

1. Sep 25, 2008

### acissej_o3

a 25-gm bullet traveling with a speed of 300m/sec strikes the block of a ballistic pendulum. the block weighs 98N and is supported by a light cord 1 m long. calculate the length of the arc through which the pendulum swings.

2. Sep 25, 2008

### tiny-tim

Welcome to PF!

Hi acissej_o3! Welcome to PF!

Hint: the bullet will be embedded in the block, so they will move together.

Use conservation of momentum to find the initial velocity, and then use conservation of energy to find the height!

3. Sep 25, 2008

### acissej_o3

Re: Welcome to PF!

i have computed for the height. i dont know how to compute for the arc... tnx for replying:)

4. Sep 25, 2008

### tiny-tim

easy-peasy!

the block moves on a circle of radius 1m …

so the cos of the angle is … ?

5. Sep 25, 2008

### acissej_o3

y is it zero?

Last edited: Sep 25, 2008