Rainbows on an oily street after it's been raining. The colors in floating bubbles. Rainbows in the sink when using dish-soap.
It would be kinetic energy. Let's say the book is weighs 10 Newtons you need to use a force of 10 Newtons to lift the book. In other words it's positive. As you move the book you're giving it energy. Namely potential energy which will turn to kinetic energy if you let it go. So you're changing it's position and energy.
Absorber, it absorbs the light, like a black shirt is an absorber..
Kepler's second law of planetary motion says that the imaginary line
from the Sun to the planet sweeps out equal areas in equal periods
of time.
It's just as true of comets, asteroids, dwarfs, coasting space probes ...
anything in the solar system that's coasting in gravity, and not firing engines.
That's why a comet moves so fast when it gets near the Sun.
