8. Khaled has a red toy that is painted with a special kind of paint. When he puts the toy under a desk lamp, it stays red. When he puts the toy under an infrared lamp, it turns blue. Why does the infrared light cause the toy to turn blue when the light from the desk lamp does not

Who was the first scientist to measure speed as distance over time?

Acar traveling at 22 m/s starts to decelerate steadily. it comes to a complete stop in 15 seconds. what is it’s acceleration?

As you are trying to move a heavy box of mass m, you realize that it is too heavy for you to lift by yourself. there is no one around to , so you attach an ideal pulley to the box and a massless rope to the ceiling, which you wrap around the pulley. you pull up on the rope to lift the box. use g for the magnitude of the acceleration due to gravity and neglect friction forces. once you have pulled hard enough to start the box moving upward, what is the magnitude f of the upward force you must apply to the rope to start raising the box with constant velocity? express the magnitude of the force in terms of m, the mass of the box.