Physics AS/A2 Thread

[mury456]

Heyy all,

This thread is there for those who are giving Physics AS or A2 in oct/nov Session
Post your questions and doubts,
and find help !


Rules :
Post questions with an attachment in the same post.

Please wait for the answer before posting another question, do not worry people will answer the question soon.

 

[mury456]

please post answer for this !

 

[destined007]

a)i) The points don't lie on the line of best fit.
ii) The line of best fit doesn't pass through origin.

b) the ball was dropped from the point not coinciding with zero displacement. Extend the graph and check the x axis. It's not passing via origin.

c)i) choose the first and the last points from the graph to calculate the gradient.
gradient= change in t^2/change in s= (260-85)x10^-3/130-50=2.19X10^-3 s^2 cm^-1

ii)s=ut+1/2at^2 where u=0 ms^-1
s=1/2at^2
2(s/t^2)=a
a=2(1/2.19x10^-3)
a=913.24 cms^-2

d)i) graph of under-root s/under root cm vs t/s
ii) looking at the equation s=ut+1/2at^2 it can be concluded that under root s is proportional to t.

 

[mury456]

can you please explain c) ii

i cnt get to understnd how the gradient is involved in this ....
the gradient in a distance-time graph is velocity

how is the value of t and s calculated ...

kindly explain the answers

 

[destined007]

The gradient is t^2/s. Therefore, s/t^2 will be the inverse of gradient. Get it?

 

[mury456]

yea ... thnkx

okii help me out wd this onee !!??


Q) Forces of 5N 3N and 4N are in equilibrium, assuming that sin37 = 0.6. Find the angle between 5N and 3N ?

im guessing we have to use cosine rule here !??

 

[destined007]

You are welcome.

 

[destined007]

yea ... thnkx

okii help me out wd this onee !!??


Q) Forces of 5N 3N and 4N are in equilibrium, assuming that sin37 = 0.6. Find the angle between 5N and 3N ?

im guessing we have to use cosine rule here !??

There's something missing in the question i believe. Please recheck and confirm.

 

[mury456]

no itz complete ... althou I do know the angle is between 3 and 5
because

sin37 = 0.6
sin37 = 6 / 10
sin37 = 3 / 5

thus the angle opposite 3 side and 5 hypotenuses side is 37

 

[destined007]

Apply sine rule.
3/sin37=4/sinx
Tell me if it's correct?

 

[sachinkhanal]

Terminal velocity

Today in our class our subject teacher asked Us about terminal velocity , We answer what we read last year but then he said us to explain the same in such a way so that an illiterate can get it .. Can any of you define or explain about terminal velocity ?
Please reply soon because it is as our assignment for tomorrow . Easy to say but tough to feel

 

[destined007]

Terminal velocity is when velocity of an object becomes constant.
If you drop a ball, its velocity will increase until it reaches it maximum. There will be no further increase in its velocity. That's the terminal velocity. At that moment, the weight of the ball and the air resistance will be equal. So there will be no acceleration.

 

[mury456]

question : Kinematics

A car is decelerating uniformly. It velocity changes from 30 - 15 ms^-1 in 75m
How much further will it travel before it come to a stop ?

 

[destined007]

2as=v^2-u^2
2a(75)=(15)^2-(30)^2
a=-4.5 ms^-2

apply 2as=v^2-u^2 again
2(-4.5)s=0^2-15^2
s=25 m

the car will travel 25 m further.
i hope its correct.

 

[mury456]

okiii ... i apparently solved it ... ill still show it here so that others may also see the answer

equation 1
v^2 = u^2 + 2 a s
solve for a
225 = 900 + 150a
a = -4.5

equation 2
v^2 = u^2 + 2 a s
solve for s
0 = 225 + -9s
s = 25

answer = 25m

 

[mury456]

2as=v^2-u^2
2a(75)=(15)^2-(30)^2
a=-4.5 ms^-2

apply 2as=v^2-u^2 again
2(-4.5)s=0^2-15^2
s=25 m

the car will travel 25 m further.
i hope its correct.

thnkx
i tried it myself too and got the same answer
yea ur right im sure it is 25m

 

[destined007]

Your welcome.

 

[mury456]

I need help with the topic Cathode Ray Oscilloscope Measurements[\B],

any links or notes would be very helpfull ...

 

[destined007]

Check these out:
http://www.physics.iitm.ac.in/courses_f ... oscope.htm

http://www.doctronics.co.uk/scope.htm

 

[destined007]

this too
http://www.schoolphysics.co.uk/age16-19 ... index.html