Astronauts who spend long periods in outer space could be adversely affected by weightlessness. one way to simulate gravity is to shape the spaceship like a cylindrical shell that rotates, with the astronauts walking on the inside surface. explain how this simulates gravity. consider (a) how objects fall, (b) the force we feel on our feet, (c) and other aspects of gravity you can think of

Answermarble and quartzite

1) what is light? light is an electromagnetic wave visible to the human eye.  2) what is a reflection? the rebounding of a light ray when it hits a mirror.3) what is the incident ray? contacts the surface of an object.4) what is the reflected ray? bounces off a reflective surface.5) what is the normal ray? perpendicular to the surface of a mirror.6) what is the angle of incidence? an angle formed by the incident ray and the normal.7) what is the angle of reflection? an angle formed by the reflected ray and the normal.8) what is refraction? (bending.)9) what is a converging lens? bring together light rays that pass through.10) what is a diverging lens? spreads out light passing through.11) focal point? the real point where the refracted rays meet when the incident rays run parallel.

Projectile motion is a form of motion experienced by an object or projectile that is thrown near the earth's surface and moves along a curve path under the action of gravity.   

This is asking what you have learned in your studies i haven't read studies and i'm not able to read your mind..