An object is at rest on an inclined plane. in which direction does the static friction force act? 1) opposite to the direction of the gravitational force 2) in the direction of the gravitational force 3) in the direction of the normal force 4) along the surface of an inclined plane in an upward direction

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?