Recent content by KingOfTwilight

First: x-component was correct but y is wrong.

You have two equations, omega = alpha * t, and fi = ½ * alpha * t^2, these equations are like v = at and s = ½at^2 in linear motion. You also have two unkwons, so you can solve both. Then use M = J*alpha.

Use conservation of momentum, remember that momentum is a vector.

The correct answer is F=f.

F does not create any force f. F creates acceleration a, which you think is caused by some force f.

F doesn't create any force. Actually it makes the object accelerate, so f should be a = F/m.

Thanks Astronuc, I can't wait.

I say clockwise too.

Gradient FAQ or guide/introduction would be marvellous! I've been trying to learn about them but I still lack some general understanding. (I can do problems but still have no "clear picture".) If someone can suggest websites, please do so. I'm still in high school so self-studying this kind of...

The friction force causes the acceleration of that mass (car). Use F = ma.

You should be able to find the acceleration. Acceleration is the change of speed divided by the time taken. You know the time, how about the speed?

Looks correct to me.

P = UI, this is the power the current heats the cable + the power the device in the other end is using.

Yes there is current if the circuit is closed. E = bvB \sin{\alpha} , here \alpha = \pi. You can deduce the latter from this: E = \frac{d \Phi}{dt} when you remember that A (t) = ab (t) = vtb .

Yes, you're right, omega = 2000 rpm. Just convert that into SI.