At a neuron's resting potential, the inside of the axon lies about 0.07 V below the outside of the axon. Using the formula for the capacitance you found in the previous problem, how much electric energy to the nearest picojoule (1 pJ = 1x10-12 J) is stored a 8-cm-long axon at this resting potential? Make sure to include LaTeX: \kappa=7κ = 7 for the lipid bilayer. Note the capacitance may differ for different axon lengths. This electrical energy stored in the membrane due to the potential difference across the membrane is used for fast, passive transport of ions during a nerve pulse. The nerve pulse, as you'll discuss in later labs, is caused by ions rushing across the membrane, driven by this potential difference (or, equivalently, driven by the energy stored in the capacitor, just like the charge being driven through the light bulb by the capacitor in the lab).

An internally reversible refrigerator has a modified coefficient of performance accounting for realistic heat transfer processes of where qin is the refrigerator cooling rate, qout is the heat rejection rate, and is the power input. show that copm can be expressed in terms of the reservoir temperatures tc and th, the cold and hot thermal resistances rt,c and rt,h, and qin, as where rtot rt,c rt,h. also, show that the power input may be expressed as 1.39 a household refrigerator operates with cold- and hot-temperature reservoirs of tc 5 c and th 25 c, respectively. when new, the cold and hot side resistances are rc,n 0.05 k/w and rh,n 0.04 k/w, respectively. over time, dust accumulates on the refrigerator’s condenser coil, which is located behind the refrigerator, increasing the hot side resistance to rh,d 0.1 k/w. it is desired to have a refrigerator cooling rate of qin 750 w. using the results of problem 1.38, determine the modified coefficient of performance and the required power input w under (a) clean and (b) dusty coil conditions. internally reversible refrigerator qout qin w high-temperature reservoir low-temperature reservoir th th,i tc,i tc high-temperature side resistance low-temperature side resistance w qin th tc qinrtot tc qinrtot copm tc qinrtot th tc

Ameter stick is pivoted at the 0.50-m line. a 3.0-kg object is hung from the 0.15-m line. where should a 5.0-kg object be hung to achieve equilibrium (the meter stick oriented horizontal and motionless)?

A10 kg box initially at rest is pulled 18 meters across a horizontal, frictionless surface by a 40 n force. what is the block’s final velocity over the 18 meters?