Why can't we just breath in the nitrogen from the air?

What is the angular momentum of the bar about the axle?

Ablock having mass m slides down an inclined plane. the force of friction between the block and the inclined plane is f, the block's weight is m g, and the normal force is n. (a) draw a free – body force diagram showing the forces acting on the block. (b) write down all relevant newton’s equations for a given situation.

Dao makes a table to identify the variables used in the equations for centripetal acceleration. what quantities belong in cells x and y?