Physics
Physics
Problem
State the mathematical expression for the work done (or equivalently the change in gravitational potential energy) when a body of mass is moved from a distance to a distance from the centre of a planet of mass .Intuitive explanation
Gravitational potential energy depends on the inverse distance between masses, not linear distance—this is the key difference from everyday potential energy like . When you move a mass in a gravitational field, you're not just multiplying force by displacement; you need to integrate the varying gravitational force over the path. The work done equals the change in potential energy, which you find by evaluating the potential energy function at both positions and taking the difference.
Intuitive explanation
Gravitational potential energy depends on the inverse distance between masses, not linear distance—this is the key difference from everyday potential energy like . When you move a mass in a gravitational field, you're not just multiplying force by displacement; you need to integrate the varying gravitational force over the path. The work done equals the change in potential energy, which you find by evaluating the potential energy function at both positions and taking the difference.