Jin knows that the initial internal energy of a closed system is 78 j and the final internal energy is 180 j. he also knows that 64 j of energy are used to do work. to find the heat added to the system, jin completes the steps below. 1. add the initial internal energy plus the final internal energy to find the change in internal energy. 2. add the change in internal energy to the energy used to do work. 3. write the answer in joules. which best describes jin's error? for step 1, he should have used 180 j as the change in internal energy. for step 1, he should have subtracted 78 j from 180 j to find the change in internal energy. for step 2, he should have subtracted the change in internal energy from the energy used to do work. for step 2, he should have subtracted the energy used to do work from the change in internal energy.

Which diagram correctly demonstrates the various forces acting on a ball moving horizontally with some speed?

Total solidification times of three casting geometries are to be compared: a sphere, a cylinder, in which the length-to-diameter ration - 1.0, and a cube. volume = 1000 cm^3 for all three shhapes, and the same casting alloy is used. a) determine the solidification times of each geometry b) based on the results of part (a), which geometric element would make the best riser? c) if the mold constant = 3.5 min/cm^2 in chvorinov's rule, compute the total solidification time for each casting.

Suppose water is leaking from a tank through a circular hole of area ah at its bottom. when water leaks through a hole, friction and contraction of the stream near the hole reduce the volume of water leaving the tank per second to cah 2gh , where c (0 < c < 1) is an empirical constant. a tank in the form of a right-circular cone standing on end, vertex down, is leaking water through a circular hole in its bottom. (assume the removed apex of the cone is of negligible height and volume.) (a) suppose the tank is 20 feet high and has radius 8 feet and the circular hole has radius 2 inches. the differential equation governing the height h in feet of water leaking from a tank after t seconds is dh dt = − 5 6h3/2 . if the height of the water is initially 8 feet, how long will it take the tank to empty? (round your answer to two decimal places.)