Recent content by yoni162

Alright I think I've realized my misconception..Gauss' law in this case only tells my the the electric flux will be 0, since there is no charge inside the surface I chose..this doesn't mean that there isn't an electric field there, it just means that all contributions of flux cancel each other...

Homework Statement A cylinder (hollow) with radius R is charged with charge Q on its outer side. What is the electric field at a point A on its center axis (inside the cylinder)? Homework Equations Electric field generated by a charged ring in distance r from its center Gauss' law...

How did I not notice that..thanks, that solved it.

Homework Statement We have a sphere with radius b, within that sphere there's another sphere with radius a. Between the two spheres we have an electric charge with density A/r. Also, we have a charge Q in the center. We need to find the constant A so that the field between a and b is...

Maybe I wasn't being clear, I was talking about the angular momentum of the masses relative to the center of mass of the 3 masses+cross. Anyway I solved the question, so thanks.

Homework Statement 4 masses are attached to a rotating cross. At some point, mass 4 is detached from the cross. What will be the angular velocity w' in which the 3 remaining masses will rotate about their center of mass (with the cross, which has no mass)? Homework Equations L(0)=L(of...

One more thing I wanted to ask..is there conservation of linear momentum in this case? Since the forces acting on the cars aren't internal forces after all..

OK I don't know if that's what you were going for, but I said: in order for the c.o.m frame of reference to remain inertial, we need to have the the net external forces=0. I know that the net external forces is the velocity of the c.o.m divided by the sum of the masses, and I want it to be 0...

Homework Statement Two cars are driving along the road at constant speeds V1, V2. At t=0 they begin to accelerate with constant acceleration a1, a2. Under what circumstances is the center of mass frame of reference inertial?Homework Equations Fext=0 ==> change in momentum=0The Attempt at a...

yeah you're right I forgot, thanks..

Homework Statement A ball is released from height h. The friction coefficient between the straight part and the ball is 'u'. I need to find the smallest h so that the ball doesn't fall off the track. The angle alpha=45 degrees.Homework Equations Work of non-conservative forces = Change in...

Hah! you're right..thanks a lot!

Homework Statement An elevator is accelerating upwards with acceleration a0. Two masses are hanging down from a pulley, connected to each other. I need to find the acceleration of m1, as viewed from within the elevator.Homework Equations The Attempt at a Solution If I look at each mass...

If you build an equation with the work of the friction force on one side and the change in kinetic energy on the other side, you'll see that the mass of the object doesn't really matter. You can actually conclude from that, the the stopping distance of a moving object (in an ideal environment)...

First thanks for the reply. I think I understand what you're saying, it a situation like this, the friction force has to be a "response" force, as in a force that is equal in magnitude and opposite in direction to a force that was applied beforehand. But what is that force? If I want to look at...