Abar on a hinge starts from rest and rotates with an angular acceleration α = 15 + 9t, where α is in rad/s2 and t is in seconds. determine the angle in radians through which the bar turns in the first 3.91 s.

Molten iron fills a mould, which has a volume of 200 cm cubed. calculate the volume when the iron cools and solidifies.

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

The table below shows the acceleration of gravity on different bodies in the solar system. on which body would a 10 kg lamp has the most gravitational potential energy when lifted to a height of 2 m? a. earth b. mars c. neptune d. uranus