# Recent content by Helly123

1. ### ##\int (\sin x + 2\cos x)^3\,dx##

Homework Statement $$\int (sinx + 2cos x)^3dx$$ Homework Equations The Attempt at a Solution $$\int (sinx + 2cos x)^3dx$$ $$\int (sinx + 2cos x)((sinx + 2cos x)^2dx)$$ $$\int (sinx + 2cos x)(1 + 3cos^2x+2sin2x)dx$$ How to do this in simpler way?

Ok sir
3. ### Find induced current, magnetic force, work in inclined plane

Homework Statement A conducting bar slides down without friction on a pair of conducting rails separated by distance d. Connected to resistor R and there magnetic field B directed upward, perpendicular to the ground over the entire region through which the bar moves. 1) find the current 2)...

5. ### Electric Force on a Charge in a Solenoid

Could it be like this? Force direction the same as Emf's ?
6. ### Electric Force on a Charge in a Solenoid

Homework Statement Since i only know the field direction, increasing go into page. Why the answer is C? Why the answer "a" ? The R and r on the pic is respected to what? Homework Equations The Attempt at a Solution Right hand rule : finger tip = current Thumbs = force Palm = B Or...
7. ### Find the minimum distance between 2 particles

Ek at min distance is zero. Ep = kQq/r_2 r_2 is the min distance K = 1/4pi.epsilon0 Ek1 + Ep1 = Ep2 + 0 Solve for r2 Thanks all
8. ### Find the minimum distance between 2 particles

Yes.. the problem i get is non constant of acceleration. @Charles Link also pointed out important thing for me.
9. ### Find the minimum distance between 2 particles

Homework Statement A point particle of mass m and charge q(>0) approaches to a point particle Q(>0) at a fixed position. When the distance between the two particles is L, the speed of the moving particle is v. The permittivity of the vacuum is denoted as Epsilon0. Find the minimum distance...
10. ### New wave after superposition (interference)

Oh. So superposition is y1 + y2 ? Why superposition not happen to be y1 - y2? How to know if both waves get destructive or constructive interference?
11. ### New wave after superposition (interference)

Ok. what is the relation?
12. ### New wave after superposition (interference)

Homework Statement 1. Homework Statement [/B] The displacement y of standing wave that is obtained by a superposition of waves : Y1 = 3 sin (2##\pi##(0.5t - 0 25 x)) Y2 = 3 sin (2##\pi##(0.5t + 0 25 x)) Homework Equations Formula for standing waves Y = 2Asinkx coswt The Attempt at a Solution...
13. ### Find the change in the Kinetic energy of an Ideal Gas

Ok. Thanks sir
14. ### Find the change in the Kinetic energy of an Ideal Gas

So, p f = 0.3 p i Not that pf 0.3 lower than pi?
15. ### Find the change in the Kinetic energy of an Ideal Gas

Wow. Thanks a lot for reviewing all questions