Recent content by astro2525

yeah I know, I'm not usually this cautious. currently a comp. science major so most of my time goes there, and this question is part of an assignment that's rather important grade wise, wanted to be as sure as possible that i was doing the right stuff jus wanted to say thanks again you were...

thank you so much for all your help. one more quick question if i may, say i had the capacitor being discharged through a resistor, from 90% of it's max value to 10% in 20 seconds. i believe the formula i would use is Vc = Voe-t/RC. the steps would basically be identical i presume? 0.9 * Vo =...

well as t gets bigger, e-t/RC goes to 0 i think .. so Vc does tend towards Vs? so my two equations are right? now i just substitute and solve?

so its maximum voltage is the voltage of the battery? at time t, Vc = 0.1 * Vs at time t+15, Vc = 0.9 * Vs ? in which case Vs would cancel leaving something like 0.1 = 1-e-t/RC & 0.9 = 1-e(-t+15)/RC ? thanks so much for all this help btw, i really appreciate it

ok, voltage across capacitor: Vc = capacitor voltage Vs = voltage on battery initially: 0.1 * Vc = Vs(1 - e-t/RC) 0.9 * Vc = Vs(1 - e(-t+15)/RC) are these right?? as time goes on, voltage on the capacitor is increasing

well, as time increases, voltage on the capacitor increases and voltage on the battery decreases, so V decreases and V(t) increases if there are five unknowns i need more equations before i do substitutions right? what am i missing?

well, i know V(t) = V0 * e-t/RC so would my equations be: V(t) = (V/10) * et/RC V(t+15) = (9V/10) * e(t+15)/RC which leaves me two unknowns, V & C. sorry i don't really understand that last part, my notes are super confusing. ;x

[Mentor's note: this thread does not use the standard homework-help template because it originated in a non-homework forum. It was moved here instead of being deleted because it had already gotten significant help.] "A capacitor is being charged from a battery and through a resistor of 20...

Sweet, thanks a lot =D

so it is ω = v / R ? ω = 3.96 m/s / .20 m = 19.8 rad/s? Btw, do you happen to know if all the other stuff is right?

care to elaborate? lol, not sure how I would go about doing that

There is a weight component parallel to the surface. If there was no weight component in the opposite direction of the tension, the car would be pulled by the cable.

Homework Statement Use the conservation of energy law to find the speed of the blocks and the angular speed of the pulley when the heavier block hits the ground. The system starts at rest. (going to include picture) http://i.imgur.com/CjB3gzK.jpg Homework Equations Moment of inertia for...

Ohhhhhh, for some reason I was thinking the bullet would travel with the block before bouncing off. Thank you so much!

.005*Vi = 2.005*Vf - .005*50 not sure where second error is =( (1/2)(m+M)*Vf^2 - (1/2)m*50^2 = (1/2)100*.05^2 ?