1. A boy moves on a skateboard at a constant velocity of 3 m-s-'. The combined mass of the boy and the skateboard is 40 kg. He catches a bag of
flour of mass 5 kg that is thrown to him horizontally at 6 m-s-!. Determine
the velocity of the boy after catching the bag of flour. (2 m-s ' in his original
direction)

Me ! mark u as brainlest! the speed of a sound wave depends on question 7 options: a) the frequency. b)the medium. c)the air temperature. d)both air temperature and medium.

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

Acaterpillar tries to climb straight up a wall a meter high, but for every 2 cm up it climbs, it slides down 1 cm. eventually, it reaches the top. when it reaches the top, it does not pull itself over so it will slide down 1 cm. what is the total displacement traveled?