Physics: Post your doubts here!

[Bishnu Dev]

You get diameter 4.81mm so for radius d/2 and convet mm to m.
In m 4.81/2/1000
Next u find the volume using 4/3pi r^3
Density =mass(kg)/volume(m^3)
Convert g to kg 0.450/1000 ÷vol and you get C as the answer.

Thanks! i forgot to calculate radius and was recklessly using value of D in the formula (4/3)*pi*r^3

 

[amina1300]

Thanks! i forgot to calculate radius and recklessly using value of D in the formula (4/3)*pi*r^3

Did you solve Q14, march 2017 ?
Do Post it.

 

[Bishnu Dev]

Did you solve Q14, march 2017 ?
Do Post it.

Component Code?

 

[Shimmery woods]

Q13 F1d1 + F2d2 =Ftdt
16000*0.6 +9000*2.1 =(16000+9000)*
28500÷2500=s
d=1.14m

thankyou so much!

 

[Shimmery woods]

Component Code?

variant 12

 

[Bishnu Dev]

Well i am not sure if this is the question you're talking about (I could only find this component for 2017 March). If so, the answer is C. Three forces in equilibrium forms a closed triangle. Since the weight of the object is 10N and the angle is 90 degrees, by using Pythagoras theorem Weight = (F1^2 + F2^2)^(1/2). ''C' and 'D' only satisfies this equation. Now if you compare the angle between the vertical line and the rope of F1 attached to the object, you will notice that F1 makes greater angle than F2. With smaller angle, Value of Cos theta increases hence force also increases (F = R*Cos theta). So F2 has greater force

 

[SohaibButt]

The first one was a bit tricky the others were easy.

Do u want me to show you how I got the answers?

Thanks for posting btw.

Umm aren't u going to show working?

 

[Holmes]

The first one was a bit tricky the others were easy.

Do u want me to show you how I got the answers?

Thanks for posting btw.

Do u want me to show you how I got the answers?
of course yes

 

[nigeller]

Question is killing me.
Please help.
Answer is D

 

[Bishnu Dev]

Question is killing me.
Please help.
Answer is D

 

[Shimmery woods]

que no 5 please!! i do get the part that the value is accurate..but why isnt it precise?

 

[Bishnu Dev]

que no 5 please!! i do get the part that the value is accurate..but why isnt it precise?

Uncertainty is 2 which means minimum value is 8 and max value is 12. Hence values are not close to each other....

 

[Shimmery woods]

que 9 explaination please ..I went for option B ..but the answer is D

 

[Shimmery woods]

Uncertainty is 2 which means minimum value is 8 and max value is 12. Hence values are not close to each other....

thankyou!

 

[Thelastmoment]

que 9 explaination please ..I went for option B ..but the answer is D

I think the total kinetic energy of the girl remains constant.Because no external forces act except for the weight and the jumping action(which in turn creates an upward force greater than the weight ( so girl moves up). Therefore,
Resultant is constant.
But kinetic energy is affected by velocity which has direction.so when girl moves up the velocity becomes (+) and when she falls (-) and at the top point zero.

Hope this helps <3 <3

 

[janedoe]

The answer in the marking scheme is C, please point the mistake in my method; from which I got the answer A.
And also, what is the correct method for solving this question?

 

[furuta]

The answer in the marking scheme is C, please point the mistake in my method; from which I got the answer A.
And also, what is the correct method for solving this question?

I=A^2
Intensity for wave 1 is given which is equal to amplitude (2*10^-2)^2
Amplitude for wave 2 is (3*10^-2)^2. Find the intensity of wave 2 by cross multiplying and the answer you'll get is C.

 

[Thelastmoment]

The answer in the marking scheme is C, please point the mistake in my method; from which I got the answer A.
And also, what is the correct method for solving this question?

Under what conditions do you suggest that the time taken is equal in both waves?

 

[Mstudent]

que 9 explaination please ..I went for option B ..but the answer is D

While she jumps and she is in the air, her velocity is decreasing uniformly (as acceleration is = -9.81) and is positive till her velocity is zero. Then she stays in mid air MOMENTARILY with velocity zero and falls with constant acceleration of 9.81 ms-1 in the OPPOSITE DIRECTION. Then as she lands on the trampoline and her velocity IMMEDIATELY CHANGES DIRECTION TO POSITIVE, and this repeats:

2 main important points:

1. acceleration AND deceleration is CONSTANT ( THUS NO CURVES, JUST STRAIGHT LINE GRAPH)
2. The line goes straight up cuz velocity changes direction immediately when she lands and is about to jump up again

HOPE THAT HELPS

 

[Shimmery woods]

While she jumps and she is in the air, her velocity is decreasing uniformly (as acceleration is = -9.81) and is positive till her velocity is zero. Then she stays in mid air MOMENTARILY with velocity zero and falls with constant acceleration of 9.81 ms-1 in the OPPOSITE DIRECTION. Then as she lands on the trampoline and her velocity IMMEDIATELY CHANGES DIRECTION TO POSITIVE, and this repeats:

2 main important points:

1. acceleration AND deceleration is CONSTANT ( THUS NO CURVES, JUST STRAIGHT LINE GRAPH)
2. The line goes straight up cuz velocity changes direction immediately when she lands and is about to jump up again

HOPE THAT HELPS

THANKYOUUU!!