What bonding is na+ci= na+ci answer quick 3

Abearing is designed to a reduce friction b. support a load c.guide moving parts such as wheels, shafts and pivots d. all of the above

Astudent is given an assignment to demonstrate diffraction. he takes a photograph of a straw in a glass of water. the straw appears bent at the water level. which best describes this example? a) this is a good example of diffraction. b) this is an example of dispersion and not diffraction. c) this is an example of refraction and not diffraction. d) this is an example of reflection and not diffraction.

What is the acceleration of a spaceship that is initially at rest and then speeds up to 220 m/s in 20 seconds