Newton's first law of motion is that an object in motion will tend to stay in motion unless an external force acts upon it.
Scenes the chair wheels are up the person is rolling backwards and if the wheels were down then the person would go forwards
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C. Chemical Energy is transformed to light energy and heat energy. The heat energy is keeping you warm and light energy is giving you the light you need to be able to read the book.
My educated guess : 21.2 deg