Orange juice is also a source of the antioxidant hesperidin. Because of its citric acid content, orange juice is acidic, with a typical pH of around 3.5.
With an average pH of 4.85 to 5.10, most coffees are considered rather acidic.
Cars run on gas. They convert the chemical energy in the gas to motion. This is where the system gets its energy. (Unless your system is the car and it moves beacuse is on a hill in which case gravitational potential energy transfers energy to this system).
