Physics: Post your doubts here!

[Ahmed Aqdam]

how B
:sView attachment 54928

Fom 12:00 to 12:30 distance coveref is 100 miles
From 12:30 to 1:30 distance covered is 200 miles.
Total distance covered = 300 mile so outside of range of cambridge
Remaining distance to covere = 80 mile but we only have fuel for another 50 miles since fuel for 300 miles is used up so emergency langding.

It has traveled 100 miles in the y direction till 12:30.
After that it travels 200sin45 in the y direction and 200cos45 in the x direction.
So total is 100+200sin45 in y direction and 200cos45 in x direction.
Square both and then add. Then take square root to get distance from Cambridge.

 

[nehaoscar]

Why will the line NOT be part of a circle?

 

[muhammadali233]

More current = More brightness
Since if you open switch then current will no longer be divided so the current flowing in the main branch will increase. Main branch is branch containing b1 and b2

and 31?

 

[princess Anu]

WHy is option B wrong??

 

[BhaiArshad]

and 31?

What is the answer? A or B?

 

[ashcull14]

Initial KE: 0.5*m*v^2 = 0.5mv^2
Initial momentum = final momentum
mv = 2m(final velocity)
final velocity = v/2
Final KE: 0.5 * 2m * (v/2)* = 0.25mv^2

but the ans is C
its nov 2013 p11

 

[muhammadali233]

What is the answer? A or B?

A

 

[ashcull14]

WHy is option B wrong??View attachment 54934

bcx it takes more time to return to XY less tim isnt possible possible as it rolls upwards

 

[eliyeap]

WHy is option B wrong??View attachment 54934

As the ball moves from X-Y, the speed is increasing uniformly. From Y-Z, it has a constant speed. They say that the collision with the wall is inelastic. So, the rebound speed is lesser than the impact speed. v=s/t When v decreases, that means that t increases. Longer time

 

[BhaiArshad]

WHy is option B wrong??View attachment 54934

Distance YZ is constant.
If speed is high then YZ is covered quickly so t is less.
If speed is low (after rebound inelastic) YZ is covered in more time.

You must also compare area under vt graph. YZ is constant so area must remain constant.

 

[princess Anu]

ans = B

 

[eliyeap]

The shaded area is the total work done right?

Yes, its the net work done

 

[BhaiArshad]

A

I don't know how to differentiate between A /B. Anyway Volt is defines as Joule per Coulomb. 9 V = 9 Joule per coulomb.
So 1 coulomb of charge carries 9 Joules.

 

[ashcull14]

 

[princess Anu]

Distance XZ is constant.
If speed is high then XZ is covered quickly so t is less.
If speed is low (after rebound inelastic) XZ is covered in more time.

You must also compare area under vt graph. XZ is constant so area must remain constant.

XY isn't constant,no? because the question says it comes to rest somewhere between XY so we don't exactly know if it returns to its initial position?

 

[DaniyalK]

but the ans is C
its nov 2013 p11

Final is half of the initial, so half of the kinetic energy is lost... Ek/2

 

[BhaiArshad]

XY isn't constant,no? because the question says it comes to rest somewhere between XY so we don't exactly know if it returns to its initial position?

Sorry. Read All XZ as YZ. I was talking about the Flat area.

Distance YZ is constant.
If speed is high then YZ is covered quickly so t is less.
If speed is low (after rebound inelastic) YZ is covered in more time.

You must also compare area under vt graph. YZ is constant so area must remain constant.

 

[princess Anu]

Yes, its the net work done

The net work done should be the area between the unloading and loading line ,no?

 

[eliyeap]

\
how B?

E= stress/strain= F/A/x/l
E=Fl/xA
E=Fl/ delta l (l^2)
E and F are both constant, so B

 

[eliyeap]

The net work done should be the area between the unloading and loading line ,no?

The area between is the thermal energy dissipated. For a rubber, when it is extended they say that there is no permanent extension, however there will be heat exerted. The shaded area is the net work done and the area under the graph is the work recovered