If a car is driven down a hill, the driver must put more pressure on the brakes to make the car stop than if it was on level ground. Explain your answer.

Calculate the amount of heat produced when 18000 coulombs of charge is transferred in one hour through a potential difference of 50v

Which of these activities increases the amount of carbon in the atmosphere?

Atoms seldom exist as independent particles in nature a) as single particles, most atoms have low potential energy b) their electronegativity is much lower when they combine with other atoms c) atoms are more stable when they combine with other atoms d) neutral particles are rare