Physics: Post your doubts here!

[Albert Einstein]

hello could you help me out on mcq questions of June 2012 p12 Q4, 13, 15, 17, 18, 19, 24, 25

Quest 4

diameter of metal rod = (3.5 + (31 x .01)) = 3.85

since cross sectional area is given by A=(pie d^2)4

area = 11.4
Ans B

....too much quest...dr

 

[Varuna0911]

its okay, thank you very much...you may do one question per day or week i would appreciate it

 

[raamish]

yes force is constant. but constant force always produces constant acceleration.
According to Newton's second law, F= ma, we can see that force and acceleration are directly proportional to each other. So when force increases uniformly, acceleration increases uniformly. And uniform acceleration means, uniform change in velocity. Hence velocity is not constant.

great got it thnx

 

[Mustehssun Iqbal]

great got it thnx

rethink it for yourself in order to remember it strongly...

 

[bamteck]

Mustehssun Iqbal or Albert Einstein or someone else Please help me for this question.
Please help me for June 2004 p2 no. 3 (b)(ii) also. I have trouble in answering.
Thank you very much in anticipation.

 

[Haseefa]

Could someone help me with this?

If a raindrop were to fall from a height of 1 km, with what velocity would it hit the ground if there was no air resistance?

 

[badrobot14]

Could someone help me with this?

If a raindrop were to fall from a height of 1 km, with what velocity would it hit the ground if there was no air resistance?

try this: no resistance means const acceleration...

use s = ut +0.5at^2
s = 0t + 0.5*9.8*t^2
as s=1000 get t.

use
v = u + at = 0 + 9.8*t
put t from prev step and get v...

do u get the right answer...? (this is a maths qustn n I like maths!)

 

[badrobot14]

Mustehssun Iqbal or Albert Einstein or someone else Please help me for this question.
Please help me for June 2004 p2 no. 3 (b)(ii) also. I have trouble in answering.
Thank you very much in anticipation.View attachment 14708

use paralellogram method of vector addition of forces to add the forces in that diagram:

http://www.tutorvista.com/physics/parallelogram-law-of-forces

at 11 min 20 sec in this vid this guy teaches that:

 

[bamteck]

Please help me for June 2004 p2 no. 3 (b)(ii)
Thanks.

 

[Mustehssun Iqbal]

great got it thnx

you're welcome!

 

[bamteck]

you're welcome!

Please help me for June 2004 p2 no. 3 (b)(ii)
Thanks.

 

[Varuna0911]

could you help me with June 2012 P12 Q13?

 

[Haseefa]

try this: no resistance means const acceleration...

use s = ut +0.5at^2
s = 0t + 0.5*9.8*t^2
as s=1000 get t.

use
v = u + at = 0 + 9.8*t
put t from prev step and get v...

do u get the right answer...? (this is a maths qustn n I like maths!)

Yes, I got it, JazakAllah Khair. ohh n this was a physics question...

Another quest, if there is no air resistance, what does it tell about the speed?

 

[badrobot14]

Yes, I got it, JazakAllah Khair. ohh n this was a physics question...

Another quest, if there is no air resistance, what does it tell about the speed?

wa iyyakum..
no air resistance means nothing stopping it from comming down so constant acceleration.. that tells us speed keeps increasing at a fixed rate (Acceleration of 9.8) until SPLAT it hits the ground.... with air resistance the speed increases till a fixed value and until that time air resistance force also increases until the upward and downward forces are equal and your drop comes down with a constant velocity.. we call that const velocit Terminal Velocity if my memory servers me right...

 

[bamteck]

Please help me for June 2004 p2 no. 3 (b)(ii)
Thanks.

wa iyyakum..
no air resistance means nothing stopping it from comming down so constant acceleration.. that tells us speed keeps increasing at a fixed rate (Acceleration of 9.8) until SPLAT it hits the ground.... with air resistance the speed increases till a fixed value and until that time air resistance force also increases until the upward and downward forces are equal and your drop comes down with a constant velocity.. we call that const velocit Terminal Velocity if my memory servers me right...

 

[Albert Einstein]

could you help me with June 2012 P12 Q13?

U must have done these type of quest in mechanics.. u r frm mru i fink??

well
its simple simultaneous enqs

Using newton(my friend) laws of motion
2g - T = 2a eqn 1

T - 6 = 8a eqn 2


U solve simultaneously u'll get a = 1.4 ms^-2

T =17.2 N

hence a=1.4 ans is option A

 

[Albert Einstein]

Mustehssun Iqbal or Albert Einstein or someone else Please help me for this question.
Please help me for June 2004 p2 no. 3 (b)(ii) also. I have trouble in answering.
Thank you very much in anticipation.View attachment 14708

Here u are basic o levels...

 

[bamteck]

Here u are basic o levels...

Please help me for June 2004 p2 no. 3 (b)(ii) too.
Thank you very much. I'm from MRU too

 

[bamteck]

simple use s = ut = 1/2at^2

find a

Note u for values s and t u should choose with the largest one or u find an average of d and t before replacing

Its not clear for me

 

[Albert Einstein]

Please help me for June 2004 p2 no. 3 (b)(ii) too.
Thank you very much. I'm from MRU too

Here u r.....
i've made it simpler as possible if still u can't then i can't do otherwise