What is the Mass of the Block in a Ballistic Pendulum Collision?

[johndoe14]

Homework Statement

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

Homework Equations

N/a

The Attempt at a Solution

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

 

[LowlyPion]

Homework Statement

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

Homework Equations

N/a

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]

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]

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]

do we assume that when the bullet collides with the block the block has the same velocity as the bullet?