(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?