Recent content by begbeg42

uhh nevermind I got it took a little reasoning but not too difficult isothermal so delta-T=0 i.e. delta-U=0 Q + W'=U-->Q=-W' W'=(delta-KE) delta-S= Q/T thanks

well wouldn't it be? it's an isothermal process?

oh haha ok maybe that's the assumption to make because otherwise calculating the delta-U would be difficult or is the delta-U of the entire system=0 i.e. unchanged?

wait since Q + W'=delta-U, where W'=work done by nonconservative/other forces i.e. the work done by the surroundings on the system W'=(delta-KE) + (delta-PE)...in this case PEi=0 and PEf=0 thus W'=1/2mvf^2- 1/2mvi^2 for both cars I know just intuivitely that when a car crashes the KE of...

S(total)=S(car) + S(car 2) + S(environment) where the values are changes in entropy delta-S=delta-q/T, where delta-q=heat and T is a constant temperature? how do I relate velocities and masses to heat?

Homework Statement Two cars each of mass 1410 kg traveling at 91 km/h in opposite directions collide head-on and come to a disastrous halt; see Figure P.38. Assume that the surrounding air and ground temperature remains fixed at 18°C. Calculate the total entropy change of the cars and...

ah thank you! what a stupid question.

just mv? then Fave=mv/delta-t?=8.91E-6/(1/1000s)=0.00891 N

Homework Statement Raindrops of mass 0.99 mg fall vertically at a constant speed of 9.0 m/s, striking a horizontal skylight at the rate of 1000 drops/s and draining off. The window size is 17.0 cm x 25.0 cm. Assume the collisions of the drops with the window are completely inelastic...

i did what kelly did and also got the wrong answer...I do not know how to apply the thing about the outside pressure please help thanks

is this problem/ piston isochoric or isobaric?

how do you solve for the final pressure & and the final volume? and is what I posted above correct? or is there some flaw I'm missing again, thank you

yes some help on this would be nice... using the ideal gas law, since nr=constant=PiVi/Ti=PfVf/Tf, thus PfVf=a constant F=PA Fspring=kx then -kx-P(outside)A=P(inside)A where A=pi(r^2) but now I am stuck...I understand that initially P(outside)A=P(inside)A and thus kx=F(spring)=0 but I am not...

nothing? help please!

Homework Statement The strobe lights on top of two tall radio towers both have a period of about 1.00 s. When turned on simultaneously, a keen observer notes that during an 813 s interval, the lights gradually fall out of synchronization and then come back into flashing synchronously. What...