Physics: Post your doubts here!

[The Sarcastic Retard]

Q1, 2a, Q4

 

[Sarosh Jameel]

Plz help me with part (II) .. its june 09

 

[The Sarcastic Retard]

Plz help me with part (II) .. its june 09

Let theta = @
Let omega = w

SQ is clearly r(sin@)
So SQ = rsin(@/t)*t Where @/t = w

 

[Sarosh Jameel]

t

Let theta = @
Let omega = w
View attachment 57781
SQ is clearly r(sin@)
So SQ = rsin(@/t)*t Where @/t = w

thanks

 

[Sarosh Jameel]

PLZ help with this !

 

[The Sarcastic Retard]

PLZ help with this !View attachment 57783

a)
When the stone will be at bottom most point, the Weight will act vertically downwards and reaction force (force excerted by glue on rod) towards the center of circle which is vertically upwards.
b)
T - W = mrw^2
15 = 0.3(0.85)w^2
w = 7.6rad/s

 

[My Name]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w10_qp_23.pdf
question 8 part b

 

[My Name]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w11_qp_21.pdf
q5 c ii

 

[Sajeeda Akeel]

Ok yeah taking the real case scenario it is clear
But then as you said "a 'centripetal' force is any force that acts towards the centre. since the mud is on an object in circular motion, it will experience a force."
Doesn't that mean the mud will experience a force towards the centre?

No...Actually the centripetal force acting toward the centre is approximately at 90 degrees of an angle to the velocity in which the object is moving.
Hence, it does not have a component that is in the direction of the velocity of the object.
So, obviously neither the object nor the mud moves toward the centre. But, yes...you can definitely state that the mud and the object both experience a force toward the centre. If this force weren't there the, the object and mud would both move off in a straight line.
There would be no circular motion.
The action of the centripetal force that ACTS TOWARD THE CENTRE basically just bends the otherwise straight-line motion of the mud and object.
I HOPE I MADE IT A LITTLE CLEAR.

 

[The Sarcastic Retard]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w10_qp_23.pdf
question 8 part b

Total current = 230/44.6
Power = I^R

 

[Sajeeda Akeel]

Could anyone explain how you deduce the answer...
Step by step!!!!

 

[The Sarcastic Retard]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w11_qp_21.pdf
q5 c ii

maxm V = 2V (I = 2/3.4 ; V = 2 * 3.4/3.4)
Minm V = 4.5 x 10^-3 (I = 2/(1500+3.4) ; V = I x 3.4)

 

[My Name]

maxm V = 2V (I = 2/3.4 ; V = 2 * 3.4/3.4)
Minm V = 4.5 x 10^-3 (I = 2/(1500+3.4) ; V = I x 3.4)

I dont get it.

 

[The Sarcastic Retard]

I dont get it.

Maximum V is when R = 0ohms.
So I when R = oohms is 2/3.4 A
So maximum V = I * R
R = 3.4
So V = 2/3.4 x 3.4 = 2V

Minimum V when R = 150ohms.
so I = 2/(1500 + 3.4) A
So V = 2/1503.4 x 3.4 = 4.5 x 10^-3V

 

[My Name]

see solution 656 at
http://physics-ref.blogspot.com/2015/05/physics-9702-doubts-help-page-131.html

I checked there first.I did not understand.

 

[The Sarcastic Retard]

View attachment 57865

Could anyone explain how you deduce the answer...
Step by step!!!!

3.8 x 10^5 will be the distance of the edge of moon to telescope (radius)
omega = 9.7 x 10^-6
When theta is so small the curvature = straight line.
We have to find Arc length which can be considered as a diameter as theta (omega) is so small.
So S = r x theta
Hence s = 3.8 x 10^5 x 9.7 x 10^-6 = 3700m

 

[The Sarcastic Retard]

I checked there first.I did not understand.

Maximum V is when R = 0ohms.
So I when R = oohms is 2/3.4 A
So maximum V = I * R
R = 3.4
So V = 2/3.4 x 3.4 = 2V

Minimum V when R = 150ohms.
so I = 2/(1500 + 3.4) A
So V = 2/1503.4 x 3.4 = 4.5 x 10^-3V

Dont u get it still?

 

[My Name]

Dont u get it still?

I think I do.thanks

 

[The Sarcastic Retard]

I think I do.thanks

Exactly which part you are not getting? I will try to simplify that.

 

[My Name]

Exactly which part you are not getting? I will try to simplify that.

No let me try once more,later.
If i dont get it I will ask.