What scale do we use to measure how acid or alkali is

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 magnitude of the resultant vector round your answer to the nearest tenth

Asher cycles 12 miles in 16 hours. what is his speed?