An astronaut , floating alone in outer space, throws a baseball. if the ball floats away at a speed of 20 meters per second, the astronaut will

The astronaut will move to the opposite direction but a lower speed. Since the particle will move. This is based on momentum since this the product of the mass and the velocity of an object. So for the case of the baseball (small mass) that is thrown fast (high velocity) can make you change your direction once you throw the ball.

Aform of energy that is reflected or emitted from objects in the form of electrical and magnetic waves that can travel through space. there are many forms of  electromagnetic  energy including gamma rays, x rays, ultraviolet radiation, visible light, infrared radiation, microwaves and radio waves.