One autumn day, ethan was sitting under a tree. he repeatedly got hit on the head and shoulders by falling acorns. he looked up at the huge oak tree and thought, "this is so much like the story of sir isaac newton and the apple tree." according to the story, what had newton discovered?

The rigid beam is supported by the three suspender bars. bars ab and ef are made of aluminum and bar cd is made of steel. if each bar has a cross-sectional area of 450 mm2, determine the maximum value of p if the allowable stress is (σallow)st = 200 mpa for the steel and ( σallow)al = 150 mpa for the aluminum. est = 200 gpa and eal = 70 gpa.

Ammonia enters the expansion valve of a refrigeration system at a pressure of 10 bar and a temperature of 18oc and exits at 6.0 bar. the refrigerant undergoes a throttling process. determine the temperature, in oc, and the quality of the refrigerant at the exit of the expansion valve.

Which atomic model was proposed as a result of j. j. thomson’s work?