How will you charge a glass rod by the method of friction

Prompta snowboarder stands at the top of a hill and decides to see if he can increase his speed on his next trip down the slope. describe one thing the snowboarder could do to incrlase his speed on the slope. explain why this would cause his speed toincrease relate one of newton's laws to this problem.

Consider a uniformly charged ring in the xy plane, centered at the origin. the ring has radius a and positive charge qdistributed evenly along its circumference. a)what is the direction of the electric field at any point on the z axis? . b)what is the magnitude of the electric field along the positive z axis? use k in your answer, where k=14πϵ0. d)the ball will oscillate along the z axis between z=d and z=−d in simple harmonic motion. what will be the angular frequency ω of these oscillations? use the approximation d≪a to simplify your calculation; that is, assume that d2+a2≈a2. express your answer in terms of given charges, dimensions, and constants

By what primary heat transfer mechanism does the sun warm the earth?