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johndoe14
Oct6-08, 02:56 PM
1. The problem statement, all variables and given/known data

A 12g bullet is fired at 1600m/s into a wooden block of a ballistic pendulum, causing it to swing back, raising up 1.40m vertically. Find mass of the block



2. Relevant equations

N/a

3. The attempt at a solution

bullet momentum= 12g*1600m/s=19.2kgm/s

LowlyPion
Oct6-08, 03:08 PM
1. The problem statement, all variables and given/known data

A 12g bullet is fired at 1600m/s into a wooden block of a ballistic pendulum, causing it to swing back, raising up 1.40m vertically. Find mass of the block

2. Relevant equations

N/a

3. The attempt at a solution

bullet momentum= 12g*1600m/s=19.2kgm/s

Welcome to PF.

What's happened to the kinetic energy of the bullet? Think maybe it got translated into the block?

johndoe14
Oct6-08, 03:17 PM
am i correct by saying that the block has a kinetic energy of____ due to the bullet

ke= .5*.012kg*1600m/s^2
= 15360kgm/s^2

LowlyPion
Oct6-08, 03:29 PM
am i correct by saying that the block has a kinetic energy of____ due to the bullet

ke= .5*.012kg*1600m/s^2
= 15360kgm/s^2

Not quite. It's V2

If it absorbed that much KE and the block and bullet was raised by 1.4m then ...

johndoe14
Oct6-08, 03:33 PM
do we assume that when the bullet collides with the block the block has the same velocity as the bullet?