Sound travels about four (4) times faster in water than it doss in air. if the speed of sound in air is 343 m/s, how long would it take sound to travel five (5) miles under water? express answer in seconds.

Two resistors r1 and r2 may be connected either in series or parallel across an ideal battery with emf ε. we desire the rate of energy dissipation of the parallel combination to be 8.75 times that of the series combination. if r1 = 105 ω, what are the (a) smaller and (b) larger of the two values of r2 that result in that dissipation rate?