An electrical current of 700 a flows through a stainless steel cable having a diameter of 5 mm and an electrical resistance of 6 104 /m (i. e., per meter of cable length). the cable is in an environment having a temperature of 30°c, and the total coefficient associated with convection and radiation between the cable and the environment is approximately 25 w/m2 k.(a) if the cable is bare, what is its surface temperature? (b) if a very thin coating of electrical insulation is applied to the cable, with a contact resistance of 0.02 m2 k/w, what are the insulation and cable surface temperatures? (c) there is some concern about the ability of the insulation to withstand elevated temperatures. what thickness of this insulation (k 0.5 w/m k) will yield the lowest value of the maximum insulation temperature? what is the value of the maximum temperature when the thickness is used?

Atennis player used a tennis racket to hit a tennis ball with a mass of 0.25 kg with a force of 5.25 newtons. how does the force the tennis racket exerted on the tennis ball compare with the force the tennis ball exerted on the tennis racket? a. the force of the tennis racket on the tennis ball is equal in magnitude and opposite in direction to the force the tennis ball exerted on the tennis racket. b. the force of the tennis racket on the tennis ball is equal in magnitude and in the same direction as the force the tennis ball exerted on the tennis racket. c. the force of the tennis racket on the tennis ball is less in magnitude and in the same direction as the force the tennis ball exerted on the tennis racket. d. the force of the tennis racket on the tennis ball is greater in magnitude and opposite in direction as the force the tennis ball exerted on the tennis racket.