8. Centripetal Forces & Gravitation

According to the inverse square law for light, if the luminosity of the Sun is $L$ and the distance from the Sun to Earth is $d$, what is the apparent brightness $B$ of the Sun as seen from Earth?

When you are traveling down a steep hill and are using your brakes a lot, which force is primarily responsible for pulling your vehicle down the hill?

When a vehicle descends a long, steep downgrade, why should the use of brakes be considered only a supplement to the braking effect of the engine, rather than the primary means of slowing down?

According to Newton's Law of Gravity, which two factors determine the magnitude of the gravitational force between two objects ($F=\frac{G}{r^2}{m}_1{m}_2$)?

A satellite is in orbit around the Earth. Which object experiences a greater gravitational force according to Newton's Law of Gravity ($F_g=\frac{G{m}_1{m}_2}{r^2}$)?

According to Newton's Law of Gravity, what effect does the gravitational force $F=\frac{\mathrm{Gm\_1m\_2}}{r^2}$ have on objects?

Which statement best describes the gravitational force between two objects?

Which of the following best describes Newton's Law of Universal Gravitation?

Which of the following equations is associated with gravitational forces and acceleration movements according to Newton's Law of Gravity?

During the process of gravitational condensation, what is the primary physical change that occurs within a cloud of gas and dust?

According to Newton's Law of Gravity, the strength of the gravitational force between two objects is affected by the mass of the objects and which of the following? (Newton's Law of Gravity: $F=\frac{G{m}_1{m}_2}{r^2}$)

Three stars, each with the mass of our sun, form an equilateral triangle with sides 1.0 x 10¹² m long. (This triangle would just about fit within the orbit of Jupiter.) The triangle has to rotate, because otherwise the stars would crash together in the center. What is the period of rotation?

A 2,000-kg spacecraft is blasting away from the surface of an unknown planet the same size as the Earth. At 1500km above the surface, an instrument onboard reads the gravitational force to be 18000 N. What is the planet's mass?