When a car is going downhill, the driver must apply more pressure on the brakes to stop than if the car were on level ground. why?

You may expect bonds between two atoms which each have n covalent lonic metallic hydrogen

Which of the following natural processes is most likely to support the formation of an underwater sinkhole? a pollution buildup from deposited minerals b limestone cave collapsing due to changes in sea level c erosion of large amounts of sand moved by ocean waves d oxidation of rock formed by chemical weathering

What is a difference between a mixture of elements and a mixture of compounds