What is energy?

(not the answer from google search.)

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.

Convection currents are caused by differences in what two things?

Astudent pushes a 60-n block across the floor for a distance of 10 m. how much work was done to move the block