Physics: Post your doubts here!

[Mathemagical]

Hey,

Could someone please show me how to work out the voltage and current across R1 and R2 respectively? Thanks!

Taking clockwise as the positive direction,
e.m.f = 1.5-1.5-1.5+1.5+1.5+1.5+1.5+1.5+1.5-1.5 = 6V

Total resistance = 1100 ohm

Current through R2 = V/R = 6/1100 = 5.5mA.

Voltage across R1 = (100/1100)*6 = 0.55V

 

[nehaoscar]

How to do??

 

[Mathemagical]

View attachment 54620
Why C?? Why multiply it by A?

Upthrust is a force. Force = Pressure*Area.

 

[nehaoscar]

Why not B?

 

[Mathemagical]

View attachment 54619
Why can't it be A??
A shows that velocity is increasing steadily, so constant acceleration so air resistance negligible right?
So why not A??

It cannot be A because the graph levels out, indicating constant velocity. If air resistance were negligible, the acceleration would always be equal to 9.81 m/s2 and the velocity would always be increasing constantly.

 

[Mathemagical]

View attachment 54622
Why not B?

B shows a straight line. The path must always be a curve.

 

[nehaoscar]

How to do this one??

 

[Ahmed Aqdam]

How to do this one??

The first liquid has mass m and volume v.
The second also has mass m and will have volume v/2 so it can have a density of 2ρ.
When mixed, the total mass will be 2m and total volume 3v/2. Hence density will be 4/3ρ.

 

[abruzzi]

It's a series circuit, so the current will be the same all around
Add up the emf of the batteries taking in note their directions
(so add up the ones facing one direction and subtract it from the others facing the other direction)

This gives total emf = 6V
Total resistance = 1000 + 100 ohms = 1100

Current = V/I
= 6/1100
= 5.5mA

V across R1 = I x R1
= 5.5mA x 100
= 0.55V

I across R2 = as I said earlier it's a series circuit, so the current is same in all components
= 5.5mA (as calculated above)

Taking clockwise as the positive direction,
e.m.f = 1.5-1.5-1.5+1.5+1.5+1.5+1.5+1.5+1.5-1.5 = 6V

Total resistance = 1100 ohm

Current through R2 = V/R = 6/1100 = 5.5mA.

Voltage across R1 = (100/1100)*6 = 0.55V

Thanks guys

 

[Mahnoorfatima]

https://docs.google.com/viewerng/vi...wp-content/uploads/2012/11/9702_s14_qp_12.pdf
16 and 35 anyone please I dont get it from that physics website of solutions at all!!

 

[princess Anu]

Try this one:
View attachment 54596

is it B?

 

[69ermalik007]

can somebody help me with these?

 

[Mahnoorfatima]

https://docs.google.com/viewerng/vi...wp-content/uploads/2012/11/9702_s14_qp_13.pdf
In question11 whats the diff bw a and b??? ANYONE??

 

[Mahnoorfatima]

What happens when the time base on the C.R.O is doubled and the Y gain is unchanged? Should the frequency remain unchanged?

 

[The Sarcastic Retard]

https://docs.google.com/viewerng/vi...wp-content/uploads/2012/11/9702_s14_qp_13.pdf
In question11 whats the diff bw a and b??? ANYONE??

11) B
Force is a rate of change of momentum.
momentum versus time graph is provided, so calculate the gradient of each option, it should be 10.
A) 5
B) 10
C) 5
d) 5/2

 

[Wolfgangs]

If I scored 'd' in my AS levels, and I did pretty well in paper 4 and 5 (75/100 and 27/30), then what is the maximum grade that I can score? Can I get an A?

 

[The Sarcastic Retard]

If I scored 'd' in my AS levels, and I did pretty well in paper 4 and 5 (75/100 and 27/30), then what is the maximum grade that I can score? Can I get an A?

B

 

[Wolfgangs]

B

If I score higher than 80 in Paper 4 and possibly full marks in Paper 5?

 

[The Sarcastic Retard]

If I score higher than 80 in Paper 4 and possibly full marks in Paper 5?

A

 

[nehaoscar]

How to do this one??