At 8 am i make a cup of tea for myself and measure its temperature to be 94° c, ten minutes later the temperature is measured to be 82° c. the ambient temperature is a constant 20° c. if i like my tea not too hot (70° c), and yet not too cold (60°c), then what is the time window i have to begin drinking? use the differential form of newton's law of cooling, and give times to the nearest minute. (15 points)

Athin nonconducting rod with a uniform distribution of positive charge q is bent into a circle of radius r. the central perpendicular axis through the ring is a z-axis, with the origin at the center of the ring. a) what is the magnitude of the electric field due to the rod at z = 0? n/c (b) what is the magnitude of the electric field due to the rod at z = infinity? n/c (c) in terms of r, at what positive value of z is that magnitude maximum? r (d) if r = 4.00 cm and q = 9.00 µc, what is the maximum magnitude? n/c