What is the mass of erath

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.

When the acceleration of a mass on a spring is zero, the velocity is at a (fill in the blank) . when the velocity of a mass on a spring is zero, the acceleration is at a (fill in the blank) .

When receiving a serve,you ideally want the first pass to be ?