# 2 Questions dealing with energy and momentum.

1. Nov 1, 2009

### cruisx

1. The problem statement, all variables and given/known data

Hi guys, i have the following questions that i am having trouble with and need some help to solve.

http://img692.imageshack.us/img692/7827/capturey.jpg [Broken]

2. Relevant equations + The attempt at a solution

Well for the first Question, i tried to uses

W = 1/2 mV22 - 1/2 mV2

and for mass i subbed in the mass of the bullet and subbed in the two different velocities and the Work was 81 888.125J
I then subbed that into (over here i used the mass of the object. )

h = 81 888.125J/ ( 0.245 * 9.8m/s2 )

and found h to be 34 105m but that seems wrong so i dont know how to solve this one.

Problem 2---------------------------------------------------------------------------------------------------------

Now for the second problem, i used

Et1 = Et2
Et1= mg(1.5m)
Et2 = 1/2 mV22 + 1/2 Kx22
mg(1.5m) = 1/2 mV22 + 1/2 (588N/M)(0.50m)2
147J = 1/2 10KgV22 + 147J

And V2 was 3.16m/s

is this correct? Help would be appreciated. Thankyou. Our teacher said that we should try to solve these questions for tomorrows lessons so we can take them up.

Last edited by a moderator: May 4, 2017