(10%) Problem 7: Suppose a hot tub containing 1400 kg of water is heated from 100°C to 400°C. Note that the hot tub is being operated in part of the country where electricity is particularly expensive -Δ 50% Part (a) what is the cost in dollars, of heating the hot tub, assuming 75.0% efficiency to account for heat transfer to the surroundings? The cost of electricity is 22 cents/kWh Grade Summary Deductions Potential cost= 11 0% 100% tan() | π| ( cosO cotan0 asin acos0 sin Submissions Attempts remaining: 3 (4% per attempt) detailed view 78 9 sinh0 atan)acotan s cosh0tanhO coho 0 END Degrees Radians BACKSPACE CLEAR Submit Hint I give up! Hints: 4% deduction per hint. Hints remaining: 2 Feedback: 5% deduction per feedback -Δ 50% Part (b) What current, in amperes, does the 220-V AC electric heater run on, if it took 4.3 h to heat up the water?

Is a  vector quantity  that refers to "the rate at which an object changes its position." imagine a person moving rapidly - one step forward and one step back - always returning to the original starting position. while this might result in a frenzy of activity, it would result in a zero velocity. because the person always returns to the original position, the motion would never result in a change in position. since velocity is defined as the rate at which the position changes, this motion results in zero velocity. if a person in motion wishes to maximize their velocity, then that person must make every effort to maximize the amount that they are displaced from their original position. every step must go into moving that person further from where he or she started. for certain, the person should never change directions and begin to return to the starting position.

The correct choice is c