Recent content by emmy

Homework Statement I don't have a question on a specific problem, I am more caught up in the determination of the phases- I'll give a general problem to use as an example: In Fig. 35-41, light is incident perpendicularly on a thin layer of material 2 that lies between (thicker) materials 1...

I recently ran a baylis-hillman reaction of 2nitrobenzaldehyde and acrylonitrile (DABCO catalyst) and after my reaction had gone to completion (determined by tlc) i extracted with chloroform/washed with brine, dried, filtered, rotovaped etc etc I ran a crude NMR and determined I did have my...

Ohhhhh my gosh this is why i miss points on exams lol! Thanks c:

Homework Statement A 382 g block is put in contact with a thermal reservoir. The block is initially at a lower temperature than the reservoir. Assume that the consequent transfer of energy as heat from the reservoir to the block is reversible. Figure 20-22 gives the change in entropy ΔS of the...

Hmm, maybe it's software malfunction? :biggrin: *crosses fingers*

Because the online homework program said so :Y

Since there are only conservative forces acting on the system, 0=ΔKE+ΔU 0=KEf-KE0+(Uf-U0) or U0-Uf = KEf-KE0 The potential energy at the beginning, U0 = Ug = mgL and Uf=0 at the bottom of the swing The Kinetic energy at the beginning, KE0=0 since the pendulum is not moving The...

Homework Statement In the Figure 8-36, the string is L = 220 cm long, has a ball attached to one end, and is fixed at its other end. A fixed peg is at point P. Released from rest, the ball swings down until the string catches on the peg; then the ball swings up, around the peg. If the ball is...

Thank you very much for your help, I'm not sure I understand completely yet, but I'm going to keep staring at it until I understand! :blushing:

So in other words, integral from -.03 to x of kxdx = 8J (k)(x2/2)|x-.03 = 8J k = 2733N/m 8/2733 = x2/2 - (.03)2/2 0.003377 = x2/2 + 0.082 = x and then i'd do the same for the negative but integrate from x to -.03?

K=Kfinal-Kinitial ? I'm armed with equations and I'm no longer sure what they do :redface: Though looking back, maybe I messed up on the original equation I used? Unless that one's completely inappropriate for this problem... Fs=-kΔx 82N=-k(-0.03-0m) k=2733N/m W=-0.5kxo2-0.5kx2...

Right, sorry I did change it when finding the spring constant but forgot otherwise. Fs=-kΔx 82N=-k(-0.03-0m) k=2733N/m To be honest, I'm not sure what elastic energy is, but it sounds like a kind of potential energy--which I don't know an equation for... External Force, Fs Work of...

Homework Statement http://edugen.wiley.com/edugen/courses/crs4957/art/qb/qu/c07/pict_7_11.gif In the above figure, we must apply a force of magnitude 82.0 N to hold the block stationary at x=-3.0 cm. From that position, we then slowly move the block so that our force does +8.0 J of work on the...

Amazing! Thank you both very much! The dot product for work makes a ton and a half more sense now :biggrin:

Ohhh, so I would use the equation of the line from the graph of acceleration vs displacement a(x)=(5/2)x (to test) a(x)=(5/2)(4)=10 F(x)=ma(x)=(12kg)(2.5)(x)= 30x W = \int_0^{5.2m} f(x) \cdot dx = W = \int_0^{5.2m} 30x \cdot dx W=15x2-15xo2 =15(5.2)2-30(0)=405.6 Joules