You build yourself a carnot engine in your garage with a thermal efficiency of 38%. the hot reservoir has a temperature of 430 c. by how many degrees should the temperature of the cold reservoir be changed (don't forget to specific increased or decreased! ) to raise the engine's efficiency to 64%?

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.

How is sound energy produced a. vibrating objects b. objects being heated c. temperature differences d. stationary objects

This is for my 8th grade science class, i really don’t understand. can someone me? , lol.