Represent the following sentence by a Boolean expression: “In a battery-powered computer, the disk drive motor 1 should be on if and only if (a) There is a disk in the drive, and (b) The disk drive is closed, and (c) The disk drive motor 2 is not on, and (d) The battery low signal is not present, and (e) The computer has started a read operation, or the computer has started a write operation.”

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

Determine the force the sun exerts on an object with a mass of 80.0 kg if that object is on the earth. what is the force exerted by the moon on the same object? what is the force the earth exerts on it?

Ascience teacher heated liquid ethanol for an experiment. when he turned up the temperature, the ethanol quickly disappeared, and a strong aroma filled the room. what happened to the ethanol?