Author Topic: physics centre  (Read 2020 times)

Offline omair

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physics centre
« on: May 25, 2010, 01:13:42 pm »
if u dont mind the important physics points are here


syllabus wise           


                     1.1 Length and time -use and describe the use of rules and
measuring cylinders to determine a length
or a volume
-use and describe the use of clocks and
devices for measuring an interval of time
-use and describe the use of a mechanical
method for the measurement of a small
distance
-measure and describe how to measure a
short interval of time (including the period
of a pendulum)               


u guys elaborate it                                             speed is scalar and velocity is vector quantity
                                                                      scalar are quantities having only magnitude

                                                                      vectors have both mag and direction

speed=total time/                               
total distance


graphs...///////-plot and interpret a speed/time graph or a
distance/time graph
-recognise from the shape of a speed/time
graph when a body is (a) at rest, (b)
moving with constant speed, (c) moving
with changing speed
-calculate the area under a speed/time
graph to determine the distance travelled
for motion with constant acceleration
-recognise motion for which the
acceleration is not constant



acceleration is rate of change of velocity/'.'.;.'...' remember the  car will be accelerating only when there will be change in its speed or direction eg a car moving at 24m/s speeds to 29m/s it is accelerating cause change in velocity right
 it will be also accelerating when the speed is 24m/s but it will be moving around or change its direction.


acceleration of free fall for
a body near to the Earth is constant 9.81m/s2 or 10m/s2

...

the motion of bodies
falling in a uniform gravitational field with
and without air resistance

remember when the object falling due to gravitation with negligible air resistance the object is falling freely

the acceleration of the body at any point during motion is same means 10 m/s2

if air resistance increase  the  acceleration of fallin object decrease  though speed will be increasing also
terminal velocity is there that stinks in all papers over here remeber resultant is zero and steps *speed of falling ob increase
*air resiistance increase *speed acceleration decrease no net force constant  velocity then give it a name terminal velocity





*mass is fixed,ammount of matter in a body scalar ,measured by beam or top paaan  is a property which 'resists' change in motion

*weight is vector , force of gravityacting on object w=mg   (n=kg*n/kg)   and changes from place to place(poles) measured by newton meter

an experiment to determine the
density of a liquid and of a regularly
shaped solid and make the necessary
calculation are important go thorough with i i remeber the mistake ws not labelling read question 145times to not lose marks in silly mistake label it ok
in this experiment know to use an rule to find dimension then desti using app formula
---
-describe the determination of the density
of an irregularly shaped solid by the
method of displacement and make the
necessary calculation here also remeber immerse the object so it touches base of measuring cylinder okkkkkkkkkkk...
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(a) Effects of forces       -state that a force may produce a change in size and shape of a body
-load ex graph to find the xtention take fihnal minus the initial  length
 hooki law states that within the elastic limit the xtention produced is directly prop to load applied

F = k x to find k f/x

limit of propotinality is til where k=f/x is constant and elastic limit is limit up
               
positive thinking means putting effort in order to achieve any thing