What is the potential energy of a 2 kg ball 15 m in the air?

Which changes would result in a decrease in the gravitational force btween two objects? check all that apply

What would people living along the coast in south florida do if there was a hurricane warning? move to locations away from the water flock along coasts to watch the natural phenomenon buy instruments to predict the exact location of the hurricane measure water levels to know the exact time of the hurricane

Four friends, a, b, c, and d are standing varying distances away from a speaker which is producing sound waves.