Prior to 1960, magnetic field strengths were usually measured by a rotating coil gaussmeter. This device used a small, multi-turn coil rotating at a high speed on an axis perpendicular to the magnetic field. The coil was connected to an ac voltmeter by means of slip rings. In one specific design, the rotating coil has 400 turns and an area of 1.4 cm2 . The coil rotates at 180 rev/min. If the magnetic field strength is 0.450T, find the maximum induced emf in the coil and the orientation of the normal to the plane of the coil relative to the field for which this maximum induced emf occurs.

Aparticle's position is given by x = 3.00 - 9.00t + 3t2, in which x is in meters and t is in seconds. (a) what is its velocity at t = 1 s? (b) is it moving in the positive or negative direction of x just then? (c) what is its speed just then? (d) is the speed increasing or decreasing just then? (try answering the next two questions without further calculation.) (e) is there ever an instant when the velocity is zero? if so, give the time t; if not, answer "0". (f) is there a time after t = 3 s when the particle is moving in the negative direction of x? if so, give the time t; if not, answer "0".