# Challenging Question

This question is one i got from uni. i just cant seem to get the right answers. Please post your worked solutions, i will tell you if you get the answer found on my sheet. Best of luck Guys, you might need it.

A 3.00 kg block of wood is suspended at rest by a thin thread attached to a supporting beam. A bullet of mass 32.0 g is fired vertica1ly upwards with velocity 415 m/s into the wood directly above it. The block and the bullet inside it move upwards together.

1 Determine the speed of the upward moving block and bullet immediately after the collision.
.
2 Calculate the total kinetic energy of the block and bullet immediately after the collision.

3 Calculate the maximum height the block and bullet reach.

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Doc Al
Mentor
Sounds like a straightforward homework problem to me!

Why don't you show what you've done so far?

Hootenanny
Staff Emeritus
Gold Member
Welcome to the Forums Willtd,

According to our forum guidelines, one is expected to show one's own efforts before asking for help. So if you post your attempted solution, we might be able to show you where've you've gone wrong.

In addition, we have dedicated Homework & Coursework forums for such questions.

Edit: The Doc Strikes again.

malawi_glenn
Homework Helper
Do you think you are some kind of a professor? hehe

Please obey the guidelines of these forums.

My Attempt

I got it!! Here is a solution for anybody who wants it. :)

1. m1v1 = m2v2
.032x415 = 3.032v
v = 4.379

2. Total Ke = 0.5 x m x v^2
= 0.5x 3.032x4.38^2
= 29.1
3. v^2 = u^2 +2as
v (final speed) = 0
s = sqrt [(4.38^2) / (2x9.8)]
= 0.98m

malawi_glenn
Homework Helper
hehe.. are you joking with us? :)

Yeh man ur cool

hehe.. are you joking with us? :)
Maybe you should help next time m8 :D

malawi_glenn