Recent content by thisischris

So 'friction' acts as resistance which corresponds to a 'drop' in emf? Should I view this 'opposed' emf in the motor as a resistance to the larger current? I still don't quite understand why the induced emf does not keep building to completely oppose the motion however? Thank you.

Hello everyone. I'm trying to understand how an 'induced' emf behaves on a current carrying conductor. Basically the example that's giving me problems is in the case of a motor, if a current starts to pass through a coil it will get an induced 'emf' to oppose the motion. And hence it...

Thank you for response. Not that I understand it that well (I haven't studied relativistic effects), although I don't think I need to at this level. Much appreciated!

In a large hadron collider at CERN, protos follow a circular path with speeds close to the speed of light. X-rays can be produced by free protons which are accelerating. Explain why this providesa source of x-rays even though the speeds of the protons are constant. Provided answer: must...

The sound waves cause the felxible front plate to vibrate and change the capacitance. Moving the plates closer togther increases the capacitance. Moving the plates apart decreases the capacitance. Explain how the sound wave produces an alternating output signal. Heres a picture of the diagram...

Thank you for everyone's help. Much appreciated. :)

Sorry, long day! I get an answer of 2.0 x106, while the provided answer is 3.0 x 105.

I asked a similar question here: https://www.physicsforums.com/showthread.php?t=612395

A VDGG is used to produce a large PD. The dome of the generator has a radios of 0.15m. It is charged and gets a PD between the dome and the Earth of 75kV. The charged stored on it is : 5.0 x 10-6C Answer: Use of E = Q/4∏εr0. 3.0 x 105 My attempt: E = kQ/r2 = 8.99 x 109 x 5.0 x 10-6 /...

A ball bearing is rolled down a ramp clamped at the edge of a bench. The ball bearing makes a head-on collosion with a marble at the bottom of the ramp. My problem lies with question B. A: Initially the ball bearing rolls down without a marble in place. The ball bearing falls a vertical...

This is exactly what I'm asking about if I understand what you mean by 'small epsilon'. I assume it's not likely to be asked in a question, which would have this behavior present?

Cheers. Right, would you mind explaining how you would without 'invoking' magnetism?

Hi there. I've got a similar question in my textbook. What do you need clarification of? What do you mean by the airplane isn't curved - I'm guessing you mean 'banking/tilting', in which case you get a value of theta which indicates that it's 'tilting'.

Hello! I'm having a bit of a struggle understanding the logic behind these two questions. A 2.2 uF capacitor is charged to a potential of 15V, and a 3.3uF capacitor is charged to a potential of 30V. The capacitors are then joined together as in the circuit diagram. When the switch s is...

I do realize that. I'm guessing though, that I'm thinking of an something that doesn't exist. Thank you for everyones help!