Does the Earth do any work on the Moon as the Moon moves in its orbit?

Kathleen climbs a flight of stairs. What can we say about the work done by gravity on her? a) Gravity does negative work on her, b) Gravity does positive work on her, c) Gravity does no work on her, d) We can’t tell what work gravity does on her.

The work–kinetic energy theorem is equivalent to a) Newton’s First Law, b) Newton’s Second Law, c) Newton’s Third Law, d) Newton’s Fourth Law, e) none of Newton’s laws.

If negative work is being done by an object, which one of the following statements is true? a) An object is moving in the negative x-direction, b) An object has negative kinetic energy, c) Energy is being transferred from an object, d) Energy is being transferred to an object.

Jack is holding a box that has a mass of $m \mathrm{~kg}$. He walks a distance of $d \mathrm{~m}$ at a constant speed of $v \mathrm{~m} / \mathrm{s}$. How much work, in joules, has Jack done on the box? a) $m g d$, b) $-m g d$, c) $\frac{1}{2} m v^2$, d) $-\frac{1}{2} m v^2$, e) zero.

A skydiver is subject to two forces: gravity and air resistance. Falling vertically, she reaches a constant terminal speed at some time after jumping from a plane. Since she is moving at a constant velocity from that time until her chute opens, we conclude from the work–kinetic energy theorem that, over that time interval, a) the work done by gravity is zero, b) the work done by air resistance is zero, c) the work done by gravity equals the negative of the work done by air resistance, d) the work done by gravity equals the work done by air resistance, e) her kinetic energy increases.

Consider an object undergoing a displacement $\Delta \vec{r}$ and experiencing a force $\vec{F}$. In which of the three cases shown below is the work done by the force on the object zero?

Which of the following is a correct unit of energy? a) $\mathrm{kg} \mathrm{m} / \mathrm{s}^2$, b) $\mathrm{kg} \mathrm{m}^2 / \mathrm{s}$, c) $\mathrm{kg} \mathrm{m}^2 / \mathrm{s}^2$, d) $\mathrm{kg}^2 \mathrm{~m} / \mathrm{s}^2$, e) $\mathrm{kg}^2 \mathrm{~m}^2 / \mathrm{s}^2$.

How far from Earth's center is the center of mass of the Earth Moon system?

Compare the fuel required for a trip from Earth to Moon with that required for the return trip.

Light from the Sun takes approximately $8.3 \mathrm{~min}$ to reach the Earth. During this time interval the Earth has continued to rotate on its axis. How far is the actual direction of the Sun from its image in the sky?

Why do scientists hypothesize that Earth is about $4.5$ billion years old?

Scientists think that Earth once had naturally existing plutonium-$239$. Suppose Earth had $10$ trillion tons of $\mathrm{Pu}-239$ when it formed. Given plutonium's half-life of $24,000$ years and Earth's current age of $4.6$ billion years, how much would remain today? Use your answer to explain why plutonium is not found naturally on Earth today.

What's the orbital radius of a satellite in a 48-hour-period circular Earth orbit?