8) A boy pushes a large 60kg box across the floor so that it accelerates at .5m/s2. He has his arms angled up from the horizontal at 10° as he applies a 100N force. What is the magnitude of the
kinetic friction coefficient between the box and the ground?

Amplify and switch electrical power and electronic signals

The answer is water molecules are split.cellular respiration and photosynthesis are complement  reactions to each other. these are reverse reactions. in cellular respiration glucose and oxygen yield water and carbon dioxide. so, when respiration begins,  glucose molecules are split. in the opposite reaction - in photosynthesis, carbon dioxide and water yield glucose and oxygen. thus,  when respiration begins, water molecules are split.

Planck decided to assume that atoms could only vibrate at certain frequencies that were whole numbers eg 2f, 3f and so on. others used to think that atoms vibrate continuously