I raised a 20 kg rock 1.5 m off the ground. I am just holding it now. Nothing is moving (except for the muscles in my back and arms that are twitching like crazy--doing work--but that's internal energy/work). So how much mechanical work am I doing now

Aprojectile is launched horizontally 10m above the ground and with an initial velocity of 15 m/s. a) determine the magnitude and direction of projectile velocity at t= 1.3s b) determine the magnitude and direction of projectile acceleration at t=1.3s

4. who was the first one to measure the speed of light and conclude that it is finite? 5. who was the first philosopher who thought the speed of light is finite? 13. what is the speed of light numerically? 14. give an example of something moving faster than light 15. give an example for some particles or waves that

What is the relationship between wavelength of light and the quantity of energy per photon?