Scientists usually write reports about their investigations. why do they do this?
a. to classify results
b. to ask questions
c. to perform experimental trials
d. to communicate their work to other scientist

Most of the volume of an atom is occupied by the

The velocity of a car traveling in a straight line increases from 0 meters/second to 30meters/second in 8 seconds. what is the average acceleration of the car?

Engines for propeller-driven aircraft are limited in their maximum rotational speed by the fact that the tip speed of the propeller must not approach the speed of sound in air (mach i). taking 6 ft as a typical diameter for a propeller of a light airplane and 1100 fils as the speed of sound, find the upper limit on the rpm (revolutions per minute) of the propeller shaft.