Thursday, March 23, 2006;12:38 pm **crisis core**
lol
i oni wish for happiness.. tml got phy spa skill A... havent study.. die... but i noe.. haha...
shall mug here!!
ok.. 1stly, 5 things i nd to noe..
1) discussion of independent variables
2) hypothesis n aim
3) diagram set up n procedures
4) safety considerations
5) reliability considerations...
ok.. wad will possibly come out... rifle n object fallin in liquid...
haha... i'll do the safety n reliability 1st.. cos mrs thai sae muz complete all.. mayb no time..
kk.. so.. safety.. dem dumb de...
rifle:
1) Make sure expt done in rifle range...
2) Make sure got warnin sign outside room..
3) Make sure no one standin beside or in front of the rifle when shootin..
4) Make sure rifle is placed on the ground when going to the target board.
5) Make sure the board behind got wall so any stray pellets will be stopped..
6) General safety.. since other den the above safety precautions.. generally safe..
* lol.. wad kinda safety precaution is this!!!*
reliability considerations:
1) repeat the stupid expt la!!!! at least 5 times for each readin...keke.. w a clear purpose
2) Make sure same type of pellets used!
3) Use same rifle.. ( dun cockster anyhow cock the rifle*haha...)
4) make sure its a closed door ceremony.. haha.. closed room conditions.. hehe... y? cos no wind ma.. wheee!
5) Mark a '
hole' made by the '
pellet' usin a marker den
're-position' the
cork sheets such that
pellet will
hit another spot... lol... * y do i always make it sound so sick?*
Discussion of variables.
dependent variable: i define depth of penetration of cork sheets s my dependent variable for my investigation. The depth of pentration can be measured by a metre rule.
Identify 1st... say how n why it affects the dependent variable...
1) Material of pellet ie.. how hard is it.. the harder the better! haha.. lol.. harder means easier to penetrate thru the target n deeper penetration.
2) Initial speed... No of aluminium sheets... larger u means deeper pentration cos takes longer time to stop the pellet..
3) shape... The more pointed it is... the greater will b the penetration. cos its pointed.. deeper into the target..
4)type of absorbent material... how hard.. softer it is.. deeper the penetration.. cos more time taken to stop the pellet completely.
5) Distance travelled by the pellet b4 hittin the target.. greater the distance travelled by pellet b4 hittin the target.. more shallow...depth of penetration... cos pellet loses more kinetic energy to work done against air resistance... thus speed of impact is lower.. less time taken to stop the pellet.. smaller depth of penetration..
choice of Independent variable...
i choose initial speed of pellets to be independent variable
Hypothesis n aim...
The kinetic energy of the pellets can be quantify as initial speed of the pellet if the mass is kept constant. Thus, the higher the initial speed of pellet, the deeper the penetration of the cork sheets.
Since I don't know how the initial speed(u) of the pellet will vary with the depth of penetration if the corksheets( d), the following relatinship is assumed.
okok.. tired ard...