No work is done by an object at rest because. 1) no force is acting on the object.
2) no distance is moved.
3) heat is not produced.
4) friction is acting on the object

What are similarities and differences of reflection, refraction, diffraction and absorption?

Road users moving into your lane, brake lights, and abrupt changes in road surface are a. rare at night b. indicators of potential hazards c. not worth worrying about before you reach them d. no problem for experienced drivers

The average density of the planet uranus is 1.27 103 kg/m3. the ratio of the mass of neptune to that of uranus is 1.19. the ratio of the radius of neptune to that of uranus is 0.969. find the average density of neptune.