Question: You're the CEO of a courier company, and you decide to select an electric car for your fleet of vehicles. A particular car has a mass of 1500 kg and is powered by 26 12-V batteries connected in series, for a total of 312 V. Batteries are rated at 100 ampere-hours, which means they can deliver 100 A for 1 h, 1A for 100 h, or any combination that equals 100 A*h. When the batteries are connected in series, the charge output of all the batteries is the same as one battery-in this case . The motor is 85% efficient in converting electrical energy to mechanical energy in the drive wheels. A test report says the car can climb a 10 degree slope at a speed of 50 km/h .
Assuming the batteries are fully charged, how long can the car maintain this speed at that angle?