What are the two factors that affect the force of gravitation?

An object moves from position +34m to the position -15m in 15 seconds. what is the total displacement? what is the total velocity?

Which is a substance that can be separated by physical means and is not the same throughout

The two most prominent wavelengths in the light emitted by a hydrogen discharge lamp are 656(red) and 486 (blue). light from a hydrogen lamp illuminates a diffraction grating with 500 lines per mm, and the light is observed on a screen 1.50 behind the grating. what is the distance between the first-order red and blue fringes?