A rod is heated at the rate of 30 watts at the middle point and is insulated at its two ends. The two half sections are cooled by convection by an ambient fluid at 20 degree Celsius with a heat transfer coefficient of 30 W/m^2 C. The diameter of the rod is 0.5 cm, its length is 18 cm and its thermal conductivity is 206 W/mC. Determine the temperature in the middle of the rod and at the insulated ends. Please describe your strategy of solving this problem.

La olla es de metal por que se calienta mas rápido, y las manijas son de madera por que así no se calientas y tienden a estar mas frías.

The figure is missing but we can answer anyway.the correct answer is "releasing the string". in fact, when the person is holding the bow and the arrow, the kinetic energy of the arrow is still zero (because the arrow is not moving). the moment the arrow is released, it acquires a velocity v, so its kinetic energy will become different from zero: where m is the mass of the arrow and v its velocity.  all the other options, instead, do not increase the kinetic energy of the system: -  pulling farther back on the string : this will just increase the elastic potential energy of the system-  holding the arrow higher: this will increase the gravitational potential energy of the system (which is given by u=mgh, where h is the height above the ground)-  decreasing the mass of the arrow: this will decrease the gravitational potential energy of the system (which is given by u=mgh, where m is the mass)