Physics: Post your doubts here!

[69ermalik007]

help needed.....

 

[Mathemagical]

Elastic energy per unit volume = (½ Fx) / AL.
= Sx / 2L [F / A = S]
= S {strain} / 2
[Young modulus, E = stress S / strain. So, strain = S / E]

Elastic energy per unit volume = SS / 2E = S2 / 2E

 

[Mathemagical]

If the heating element is glowing light red, it's between 800 and 900 degrees.

 

[princess Anu]

 

[waqas123]

Try this one:

 

[nehaoscar]

How to do this one?

 

[The Sarcastic Retard]

View attachment 54599
How to do this one?

C ?

 

[nehaoscar]

C ?

Nope ... it's B

 

[nehaoscar]

How to do this one??

 

[Mahnoorfatima]

View attachment 54601
How to do this one??

It's a simple parallel and series circuit. Look the resistor with the junction is parallel to the three resistors with no junction between them. So, add 10+10+10 = 30 then solve for 30 and 10 as in a parallel circuit. Thus product/sum = 10x30/10+30 which is 7.5 which is B ie between 1 and 10 ohms.

 

[nehaoscar]

What are the correct estimated values for A,B and C?

 

[Abdul Hanan]

If the heating element is glowing light red, it's between 800 and 900 degrees.

Elastic energy per unit volume = (½ Fx) / AL.
= Sx / 2L [F / A = S]
= S {strain} / 2
[Young modulus, E = stress S / strain. So, strain = S / E]

Elastic energy per unit volume = SS / 2E = S2 / 2E

Thanks
any idea of the third one?

 

[nehaoscar]

Read the green writing first

 

[Abdul Hanan]

thanks

 

[nehaoscar]

View attachment 54612
thanks

C - the atom with the highest mass to charge ratio has the lowest speed

 

[Abdul Hanan]

View attachment 54599
How to do this one?

for this one use ratio.
voltage not divided as its a parallel circuit
both will get 12 volts total each
for x and y only consider first resistor in each sequence
the 2000ohm will get 8v
and the resistor with 500ohm will get 4v
so pd. is 8-4=4v

 

[Mathemagical]

View attachment 54601
How to do this one??

Take the 3 10 ohm resistors on the right to be one 30 ohm resistor connected in parallel with the 10 ohm resistor.

 

[nehaoscar]

Why 2 significant figures... why not 3??

 

[nehaoscar]

How??

 

[nehaoscar]

Why B?
Don't the wheels exert a force shown by red?
So shouldn't the force by road be D (shown in blue)?
So why is it B??