IGCSE/GCSE/O & A Level/IB/University Student Forum
Qualification => Subject Doubts => IGCSE/ GCSE => Sciences => Topic started by: a7medokool on May 24, 2009, 03:58:04 pm
-
Hello could any 1 tell me how to do Q 1 c and D on this physics paper
-
hi, is this paper 3 or 6?
-
yea yea sry didnt mention the paper its Paper 3
-
the one about friction with 14 newton force right?
-
hmmm yea and could u help me to 1B too how to calcluate the mass of the trolley
-
alright
-
So shogun did u figuire it out yet?
-
bii)the equation is:
force=mass* acceleration
biii) f=ma
where f=force
m=mass
a=acceleration
so here a=2 and 'm' is giben as 12kg
so to find resultant force (f): 12*2=24N
ci)to find the total resultant force u have to add 24N and 14N (given in the question) we need to find 'a' (acceleration)
so 24+14=38N(total resultant force)
then use the formula (f=ma)
so it would be 38N=12*a
then by changing position (algebra) it will become 38/12
u get aceeleration 'a'= 3.17 meter per second square (m/s^2)
ci) use the formula to find velocity which is (velocity = acceleration*time) where 'a'=3.17 (from previous answer) and 't'=2.5s (given in the question)
so then 3.17*2.5
u get= 7.9m/s
d) the car moves with uniform acceleration. ((because at original angle of incline. it didnt accelerate because no resultant as friction force was same as the acceleration of the car.but here lubrication was added so friction froce was reduced and there was a resultant force (the accleration) thus the car aceelerated.))
any confusion or difficulty plz do ask me, im all here
-
Hmmm this is the 2nd variant Questions? right
I was aking about the 1st
-
oh ok
then i ll try to find out the first variant one..
-
Its in the site Both variants are there
-
hey if u can post the question its excelllent...if its too long its ok i am trying to download the 2st varient past paper
-
umm getting it sorry cuz the downlad took time
-
k.. heres ur answer..
1 c.) use the formula F = m *a....therefore 0.7 = 0.8 (mass of trolley) * a
=> a = 0.7/0.8 = 0.875
d.) 1.) use the formuala v = u + at
u = 0, v = at
look at the table the acceleration of the trolley is 0.5 when the weight is 0.4
therefore v = 0.5 * 1.2 = 0.6 m/s
d. 2.) use the formula s = ut + 1/2 at(2)
u = 0
therefore s = 1/2 at(2)
======================================
hope it helped u ...!! :)
= 0.5 * 0.5 * 1.2 *1.2 = 0.36 m
-
how do u do question 2(d) on the nov 2008 paper 3? on any variant, doesn't matter...
-
you have to add the forces applied by the mass...
if u take a mass of 200 g and place it 4 m from the pivot, then you have to put the 100g 8m from the pivot on the opposite side to balance it...therefore the 200g is apllying 2 N of force and 100g --> 1 N of force
therefore the total force is 3 N..
add this to the weight of the disc that is 200g = 2 N
therefore tha answer is 2+3= 5N
it depends on the masses u have taken
a certain combination could give 7N too as the answer..
hope it helped u
-
thanks eddy, it helps tons! easier than i thought it was!
-
welcome
-Adi
-
Thanks eddi appreciate it ;)
-
welcome
-ADi