A simplified experiment showing the setup of a pith ball (a circular object) attached by a string to an insulated stand. The researcher tested how far away a charged glass rod can be held while still causing an attraction to the pith ball. Which statements accurately describe this experimental design? Select ALL that apply. A) An appropriate control could be a non-charged glass rod used for comparison. B) The dependent variable is the distance of the glass rod is from the pith ball. C) The independent variable is the distance of the glass rod is from the pith ball. D) The dependent variable is the level of attraction that the pith ball has to the charged rod. E) The independent variable is the level of attraction that the pith ball has to the charged rod.

Write short note on the following ; collision theory, rotation angle and angular velocity, centripetal acceleration, coriolis force, and newton's law of gravitation.

Askydiver weighing 140 lb (including equipment) falls vertically downward from an altitude of 19,000 ft and opens the parachute after 18 s of free fall. assume that the force of air resistance, which is directed opposite to the velocity, is of magnitude 0.55|v| when the parachute is closed and is of magnitude 14|v| when the parachute is open, where the velocity v is measured in ft/s. assume that acceleration due to gravity has magnitude 32 ft/s/s; remember that weight is the product of mass and gravitational acceleration. (a) find the speed of the skydiver when the parachute opens. (b) find the distance fallen before the parachute opens. (c) what is the limiting velocity vl after the parachute opens? (d) determine how long the sky diver is in the air after the parachute opens. (e) plot the graph of velocity versus time from the beginning of the fall until the skydiver reaches the ground.

The solar panels used by mark function because of the photoelectric effect. light shines on the cells causing electrons to be ejected from the metal, which produces an electric current. at night on mars, no light will fall on the solar cells and no electric current will be generated. according to your notes, what type of light is typically needed to cause the photoelectric effect? a)visible b)ultraviolet c)infrared