CANT DO IT i nd herlp For numbers 14a-14d, tell which expressions require you to rename mixed numbers before you can subtract.

14a. LaTeX: 5\frac{2}{5}-2\frac{1}{4}5 2 5 − 2 1 4
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14b. LaTeX: 5\:-\:2\frac{7}{8}5 − 2 7 8
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14c. LaTeX: 7\frac{2}{3}\:\:-\:6\frac{1}{8}7 2 3 − 6 1 8
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14d. LaTeX: 9\frac{1}{6}-5\frac{2}{3}9 1 6 − 5 2 3
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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

Suppose a soccer ball is kicked from the ground at an angle 20.0º above the horizontal at 8.00 m/s. the y-velocity is determined to be 2.74 m/s. how long will the ball be in the air? assume the ball lands at the same height at which it was kicked.

Which of the following examples illustrates static friction? a box sits stationary on a ramp. a ball rolling on the lawn eventually comes to rest. a car rounds a curve on a road. a fish swims upstream.