A screen door spring is stretched 0.299 m, and exerts a 64.7 N force on the door. What is the spring constant of the spring? (Unit = N/m)​

15. give an example for some particles or waves that are moving faster than light in everyday life 16. what is a laser? 17. what is an oscilloscope? 18. what does it means practically that nothing is faster than light in vacuum? 19. what is vacuum?

A26 cm object is 18 cm in front of a plane mirror. a ray of light strikes the object and is reflected off the mirror at a 42-degree angle. what is the angle of reflection? degrees what type of image is formed? what is the size of the image? cm

Light traveling in a medium with a refractive index 1.19 is incident on a plate of another medium with index of refraction 1.79. at what angle of incidence is the reflected light fully polarized?