The table below shows four examples of pairs of objects, their masses, and the distance between them. In which example is the gravitational force of attraction between the two objects the greatest?

Which changes of state do the labels represent? a: b: c:

When the displacement of a mass on a spring is 12a the half of the amplitude, what fraction of the mechanical energy is kinetic energy? at what displacement, as a fraction of a, is the mechanical energy half kinetic and half potential?

What can you increase the strength of an electromagnet by