17.3 + 17.5 Energy in a gravitational field

Because it simplifies calculations for objects far from Earth

Because Earth's surface is always the reference point

Because gravitational acceleration is constant everywhere

Because potential energy is always zero at Earth's surface

By measuring the temperature change of the mass

By calculating the work done on the mass to move it to a point

By finding the speed of the mass at that point

By observing the color of the mass

The force per unit mass at a point

The work done per unit mass in bringing it from infinity to the point

The energy transferred to a mass at that point

The speed a mass would have at that point

It is zero at infinity.

It increases as a mass approaches another mass.

It is more negative near larger masses.

It is always positive.

g = F/m

g = GM/r^2

g = -ΔV/Δr

g = GMm/r^2

Mass of the Moon and its radius

Mass of the Earth and its radius

Distance from Earth to Moon

Gravitational constant and distance from Sun

It calculates the change in gravitational potential energy between two points.

It determines the speed required for a satellite to escape a planet's gravity.

It measures the mass of the satellite.

It finds the time taken for a satellite to complete one orbit.