Physics: Post your doubts here!

[Xtreamer]

Anyone Got some time management tips PLEASE SHARE!

 

[Xtreamer]

View attachment 54900
Why is resultant force zero?

Cuz Electric Field exerts a constant force so +Q and -Q 's have equal forces

 

[Ahmed Aqdam]

View attachment 54898
How B??
Y = FL/AX
L halves and A is reduced by 1/4th so shouldn't it be C??

Wire is of same steel so same Young Modulus. The difference will be in extension.

View attachment 54899
How B??
strain is deltaL/L so it it that delta l is proportional to L?

Compression is proportional to length but also inversely proportional to area of cube.

 

[princess Anu]

help me with this pleaseee. Ans is A View attachment 54896

Thanks a TON!
This is the last one, please
Ans is C

 

[Ahmed Aqdam]

Thanks a TON!
This is the last one, please View attachment 54901
Ans is C

All linear dimensions are one tenth so volume will be 1/1000. Same material is used so density is same and mass should also be 1/1000 to maintain same density. Weight depends on mass so it will also be 1/1000.
Area is 1/100 as 1/10 is squared.
Hence stress is (1/1000)/(1/100)=0.1

 

[Studydayandnight]

HELPPP!!!!!!!!

What's the answer?!

 

[Studydayandnight]

Driving force = ma = 1800 * 2 = 3600N


Moment due to weight = 0.1 * 10 * 9.81 = 9.81 clockwise
Moment due to pulley = 0.02*9.81*60 = 11.77 anti cw
difference is 1.962 anti cw, so we need 1.962 in cw direction, which we get by placing 50g on the 44cm mark.

Where'd you get the 10 from?

 

[Ahmed Aqdam]

There are 500 lines per mm so 500*10^3 lines per m. Their spacing is 1/500*10^3=2*10^6.
n λ=d sin θ so divide this d by the wavelength to get 3.33.
Hence there are 3 images on each side and 1 in the middle so 7 total.

 

[princess Anu]

Why is C wrong??( ans is A)

 

[Studydayandnight]

How do we do this? :'(

 

[princess Anu]

Isn't statement B wrong? because conventional current is from positive to negative ,no ?

 

[Studydayandnight]

There are 500 lines per mm so 500*10^3 lines per m. Their spacing is 1/500*10^3=2*10^6.
n λ=d sin θ so divide this d by the wavelength to get 3.33.
Hence there are 3 images on each side and 1 in the middle so 7 total.

Isn't mm into m, 500 x 10^-3?

 

[saturn21]

Help needed! Answer is A

 

[Aly Emran]

Someone plzz help me on this thanks in advance
Q9 and Q10... I didnt get it :/

This is a repeat qstn but i still didnt get it :/

Any quick way to calculate the energy except for counting boxes... Its time consuming...


I didnt get it.... Why isnt it C? I mean the gradient of I/V should be highest so that V/I should be lowest and R=V/I so R should be lowest...

 

[eliyeap]

I got two problems.
View attachment 54874 View attachment 54875

Can I know the answer for Q24?
For Q 20: At P (The pressure is balanced): 16000-8000= 13600( H1-H2)9.81
H1-H2= 6cm
Ans D

 

[saturn21]

How do we do this? :'(

I hope this helps ^_^
Ignore my messy handwriting )

 

[Aly Emran]

Help needed! Answer is AView attachment 54912

Make two equations:
1g-T=1a
T=2a

Subtract two equations:
1g=3a
a=3.27ms^-2

2as=v^2-u^2
u=0, a=3.27, s=0.5
underroot(3.27*2*0.5)=v
V=1.8ms^-1

 

[ashcull14]

 

[saturn21]

Someone plzz help me on this thanks in advance
Q9 and Q10... I didnt get it :/
View attachment 54905
This is a repeat qstn but i still didnt get it :/
View attachment 54906
Any quick way to calculate the energy except for counting boxes... Its time consuming...
View attachment 54907
View attachment 54909
I didnt get it.... Why isnt it C? I mean the gradient of I/V should be highest so that V/I should be lowest and R=V/I so R should be lowest...
View attachment 54910
View attachment 54911

 

[DaniyalK]

Where'd you get the 10 from?

Weight acts at the 50 cm mark, so the distance from the pivot of the weight is 10 cm