Posted by **Confused** on Monday, December 5, 2011 at 5:02pm.

Liam fires a bullet into a block suspended by two cables, embedding the bullet in the block. The mass of the bullet is 5g and the mass of the block is 1g.

1) If the maximum height of the block is ,h, is 35 cm, how fast was the bullet originally moving?

(can you explain the steps i'm really confused)

- PHYSICS HELP MEEE SO CONFUSED -
**Anonymous**, Monday, December 5, 2011 at 5:08pm
I think there's more to this question.

Are the cables there to provide resistance to motion of the block? If so, what parameters?

Is the bullet fired straight up?

conserve momentum as the moving mass changes.

- PHYSICS HELP MEEE SO CONFUSED -
**drwls**, Monday, December 5, 2011 at 5:34pm
1) From the height H that the block+bullet rises, assuming conservation of energy for the process, calculate the initial velocity V' of the block after the bullet is embedded.

(m+M) V'^2/2 = (m+M) g H

V' = sqrt(2 g H) = 2.62 m/s

2) Momentum (but not mechanical energy) is conserved during the bullet-embedding process. If V is the initial bullet velocity,

mV = (m+M) V'

Solve for V.

m is the bullet mass and M is the block's mass.

Are you sure the block is lighter that the bullet?

- PHYSICS HELP MEEE SO CONFUSED -
**confused**, Monday, December 5, 2011 at 9:51pm
oops its 1 kg

## Answer this Question

## Related Questions

- AP Physics - Liam fires a bullet into a block suspended by two cables, embedding...
- physics - A heavy wooden block rests on a flat table and a high-speed bullet is...
- physics - A heavy wooden block rests on a flat table and a high-speed bullet is ...
- Physics - A 2.50g bullet, traveling at a speed of 425m/s, strikes the wooden ...
- Physic - A 60-g bullet fired at two blocks resting on a surface with coefficient...
- Mechanical engineering - A bullet of mass 50 grams is fired horizontally into a ...
- pHysics !! - A 20-g bullet is fired horizontally into a 980 g block of wood ...
- physics - A 12.0 g bullet is fired into a 13.9kg wooden block that is hanging ...
- physics - A block of wood with a mass of 1300g is sitting on a horizontal ...
- Physics - A heavy wooden block rests on a flat table and a high-speed bullet is ...