A2.62g sample of a substance suspected of being pure gold is warmed to 72.3∘c and submerged into 15.6g of water initially at 24.8∘c. the final temperature of the mixture is 26.0∘c. what is the heat capacity of the unknown substance?

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