Do all engines operate at less than 100 percent efficiency because they conduct heat

all engines operate at less than 100 percent efficiency because they EMIT heat. ;)

They EMIT heat is the correct answer

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.

a sonic boom is a loud boom that breaks the sound barrier

explanation: