What is the condition required for an object to follow the curvature of the Earth?

Why do projectiles have curved paths?

Show that the gravitational force between two planets is quadrupled if the masses of both planets are doubled but the distance between them stays the same.

Why is centrifugal force in a rotating frame called a "fictitious force"?

Why do you do no work on a $25-\mathrm{kg}$ backpack when you walk a horizontal distance of $100 \mathrm{~m}$ ?

State the law of conservation of momentum. Explain it for a system with only internal forces.

In what ways might Axum be viewed as a smaller-scale version of the classical civilizations of Eurasia? In what ways did it differ from them?

The long-run Phillips curve illustrates which of the following? A. a positive relationship between unemployment and inflation B. a negative relationship between unemployment and inflation C. that unemployment will always return to the NAIRU D. that unemployment will adjust so that the economy experiences 2% inflation E. that output will adjust so that there is no unemployment or inflation in the long run

The Earth has a ___ that causes compass needles to point north.

An earth satellite in a 100-mile-high circular orbit around the earth has a velocity of approximately 17,500 miles per hour. If this velocity is multiplied by $\sqrt{2}$, the satellite will have the minimum velocity necessary to escape the earth's gravity and it will follow a parabolic path with the center of the earth as the focus.

Find the escape velocity of the satellite.

In what way is Earth like a hard-boiled egg?

For a satellite in earth orbit, the speed v in miles per second is related to the height h miles above the surface of the earth by $v=\sqrt{\frac{95,600}{4000+h}}$. Suppose a satellite is in orbit 15,000 miles above the surface of the earth. How much does the speed need to decrease to raise the orbit to a height of 20,000 miles?

If a galaxy moving away from the Earth has a speed of 1000 km/s and emits 656 nm light characteristic of hydrogen (the most common element in the universe). (a) What wavelength would we observe on the Earth? (b) What type of electromagnetic radiation is this? (c) Why is the speed of the Earth in its orbit negligible here?

(a) How long did it take for a message sent from Earth to reach the first astronauts on the Moon? (b) How long will it take for a message from Earth to reach the first astronauts who arrive on Mars; assume Mars is at its closest approach to Earth $\left(78 \times 10^{6} \mathrm{km}\right) ?$