I'd say ground. <span>Voltage in the US is 110-120 volts while in other countries it is 220-240 volts. if you have a 110-120 volt appliance, you need a step-up transformer (110 to 220)before you could use it in a 220 volt power supply.</span>
The answer is C. I hope this helps you.
Answer:
Friction force is the force that one object exerts in another when the two rub against each other. Most of the time, friction force opposes the motion of an object.
Explanation:
