Recent content by Lokhtar

Homework Statement A child has a toy of weight 100N which is attached to a string. The toy is initially at rest on a rough horizontal plane. The child picks up the string and pulls it so that the string makes an angle of 16 degrees with vertical. If the coefficient of friction between the...

I'm trying to look at the book and trying to visualize the forces, but I don't quite get it.

Well, if I use the right hand rule, and curl my fingers towards I, my thumb points straight up. Counterclockwise? Up? I think I am missing something conceptually, perhaps with the application of RHR.

Homework Statement Two conducting loops carry equal currents I in the same direction as shown in the figure. If the current in the upper loop suddenly drops to zero, what will happen to the current in the lower loop according to Lenz’s law? (a) The current in the lower loop will decrease...

Homework Statement Why is parallel resistance the reciprocal of all individual resistances? Homework Equations V=IR The Attempt at a Solution Well, since V is constant and I is different, you can write it as I=V/R, and since V won't change, you can make it I=V*(1/R1+1/R2),etc...

Yes, I think so. The question is a followup which simply asks if the coefficient of friction would change if that flat surface were now placed on an incline (weights and everything would remain the same, except this time there would obviously be no movement due to the incline). It doesn't ask...

The question is conceptual. There are no numbers given. If you had a certain coefficient of friction on a horizontal surface, and then you changed it to an incline, would the coefficient of friction change?

A followup question is "would the coefficient of friction be different if the situation looked like this (angle of 40 degrees)?": (Switch m1 and m2, sorry for the inconsistency in labeling). I think it would be different, because now you have to find the coefficient of friction only in the x...

Homework Statement I have a system that looks like this: http://dept.physics.upenn.edu/courses/gladney/phys1/homework/images/half_Atwood.gif m2 mass is 0.07kg. The m1 mass is gradually increased. Basically, if you tap it, m2 starts moving by itself at constant speed when m1 is at 0.03kg...

Homework Statement On a spacecraft , two engines are turned on for 684s at a moment when the velocity of the craft has x and y components of Vox=4370 m/s and Voy = 6280 m/s. When the engines are firing, the craft undergoes a displacement that has components of x= 4.11x10^6m and y =...

I have a amateur question regarding pi. I know what pi is, in a general sense, but I am looking at equations (e.g, the cosmological constant, Heisenberg's uncertainty principle, etc) where pi appears, but I do not see any relation to circles in those equations. I am sure there is, but I just...