Physics: Post your doubts here!

[shinnyyy]

Its B ....M2/M1
Momentum bfr explosion is 0
so.... 0=M1V1-M2V2
Make V2/V1 subjeact...nd u get M2/M1 as ans

Shouldn't it be as M1/M2?

 

[shinnyyy]

Its B ....M2/M1
Momentum bfr explosion is 0
so.... 0=M1V1-M2V2
Make V2/V1 subjeact...nd u get M2/M1 as ans

Oh now I got it.

 

[Wkhan860]

View attachment 55121 I need the working and explaination for these two questions.plz help me

In qtn 21 use the formula 'P=VI' ti find input power
Thn find output power by Using formula 'P=mgv' (derived frm Fv)
Thn use effiviency formula whch is (Power output/Power input)*100

 

[shinnyyy]

In qtn 21 use the formula 'P=VI' ti find input power
Thn find output power by Using formula 'P=mgv' (derived frm Fv)
Thn use effiviency formula whch is (Power output/Power input)*100

From where 'P=mgv' came from?

 

[Wkhan860]

From where 'P=mgv' came from?

Derived from 'P=Fv'
as F=mg....i substituted 'mg' in place of F in the equation.

 

[shinnyyy]

Derived from 'P=Fv'
as F=mg....i substituted 'mg' in place of F in the equation.

Thanks
and what about the other question ? Can u solve that too?

 

[Wkhan860]

View attachment 55121 I need the working and explaination for these two questions.plz help me

Qtn no 22 is A i reckon
To find efficiency use Energy output/Energy Input
Energy output is (P*t)
Energy input is (energy frm all coal)*number of trains
Thus PS/NMJ
In bith qtns use the efficiency formula

 

[raining]

how to solve (i) ?

 

[raining]

how to solve (I) ??

 

[shinnyyy]

Qtn no 22 is A i reckon
To find efficiency use Energy output/Energy Input
Energy output is (P*t)
Energy input is (energy frm all coal)*number of trains
Thus PS/NMJ
In bith qtns use the efficiency formula[/QUOTE

Energy input is (energy frm all coal)*number of trains??? HOW ? Shouldn't it be just the energy from all coal?

 

[shinnyyy]

There's another question from forces unit :
If a car is moving in a horizontal direction then in which direction the net force will act on the car.secondly how we'll draw the vector diagram for this question.

 

[shinnyyy]

Can anyone explain me how to solve Q8?

 

[shinnyyy]

q21?

 

[shinnyyy]

How we have to solve this question and what's the logic behind the ans.

 

[shinnyyy]

Bilal Khan before leaving plz help me with the questions(doubts) which I have posted above

 

[Wkhan860]

View attachment 55139
Can anyone explain me how to solve Q8?

For the goods train apply the formula ((u+v)/2)*t
N for express train use s=ut+0.5at^2
Solve them simultaneously or substitute the values
U will get 40sec as ans (D)

 

[shinnyyy]

For the goods train apply the formula ((u+v)/2)*t
N for express train use s=ut+0.5at^2
Solve them simultaneously or substitute the values
U will get 40sec as ans (D)

I have tried to solve the question but I'm stuck in the mid, now idk how to solve it further
As you have told to use that use but in the question V is not given so how how I'll know if u=10 or if v= 10
And one thing more, why we'll solve that simultaneously? ?
N can u plz solve the other two questions as well ..please

 

[Wkhan860]

View attachment 55158 I have tried to solve the question but I'm stuck in the mid, now idk how to solve it further
As you have told to use that use but in the question V is not given so how how I'll know if u=10 or if v= 10
And one thing more, why we'll solve that simultaneously? ?
N can u plz solve the other two questions as well ..please

Thy hav said constant speed....whch means thn speed will remain same...so v nd u will both be 10
Theres no need to solve simulataneously if u dnt want to.
'S' will be same so ((10+10/2))*t=(0*t+0.5*0.5*t^20

 

[shinnyyy]

Thy hav said constant speed....whch means thn speed will remain same...so v nd u will both be 10
Theres no need to solve simulataneously if u dnt want to.
'S' will be same so ((10+10/2))*t=(0*t+0.5*0.5*t^20

I got it ^_^
Thanks
Please explain me the remaining questions too .

 

[Wkhan860]

I got it ^_^
Thanks
Please explain me the remaining questions too .

Uhm..wait lemme try
I couldnt do the density qtn ill try the other 1