1. Compute the cost per hour at 8 cents per kw-hr of electrically heating a room if it requires 1 kg per hour of anthracite coal having a heat of combustion of 8000 kcal/kg. 2. The lights on a car are left on. They dissipate 95 watts. How long will it take for the fully charged 12-volt battery to run down if the battery is rated a 150 ampere-hours (A-hr)? 3. What is the cost of electrically heating 50 liters of water(50kg) from 40 degrees C to 100 degrees C at 8 cents per kw-hr? 3. For the first 2 I honestly don't know how to start or what to do. For the 3rd one, I multiplied 50*4.18*60 to get the joules. Than I multiplied that by the 8 cents. The answer I got was 1 dollar. I'm not sure if this is right, the problem does not give the time it takes, so I don't know how the 8 cents per kw-hr would work.