1. a certain cd has a playing time of 74 minutes. when the music starts, the cd is rotating at an angular speed of 4.70×10(2) revolutions per minute (rpm). at the end of the music, the cd is rotating at 2.40×10(2) rpm. find the magnitude of the average angular acceleration of the cd. express your answer in rad/s².
2.the pedals of a bicycle rotate in a circle with a diameter of 40 cm. what is the maximum torque a 64-kilogram rider can apply by putting all of her weight on one pedal?

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