Exam 4: Making Sense of the Universe: Understanding Motion, Energy, and Gravity

The force due to gravity between two objects can be described using the equation Fg = G M1 M2 / d2. In this equation, what does d represent?

The mass of Jupiter can be calculated by

Suppose it takes 6 seconds for a watermelon to fall to the ground after being dropped from a tall building. If there were no air resistance, so that the watermelon would fall with the acceleration of gravity, about how fast would it be going when it hit the ground?

Imagine another solar system, with a star of the same mass as the Sun. Suppose there is a planet in that solar system with a mass double that of Earth orbiting at a distance of 1 AU from the star. Thinking about Newton's version of Kepler's third law, what (approximately)is the orbital period of this planet? Explain your answer.

Suppose you kick a soccer ball straight up to a height of 10 meters. Which of the following is true about the gravitational potential energy of the ball during its flight?

Suppose you are in an elevator that is traveling upward at constant speed. How does your weight compare to your normal weight on the ground?

Give an example in which thermal energy might be converted to gravitational energy.

According to the universal law of gravitation, if you double the masses of both attracting objects, then the gravitational force between them will

To measure the mass of an astronomical object, one can observe the orbital period and distance of a companion.

The force due to gravity between two objects can be described using the equation Fg = G M1 M2 / d2. According to this equation, if the mass of the second object were greater, what happens to the gravitational force between them?

Where does the energy come from that your body uses to keep you alive?

Planets with larger orbital radii have longer orbital periods because they both have a longer distance to travel in each orbit and move more slowly.

As long as an object is not gaining or losing mass, a net force on the object will cause a change in

Newton's second law states: sum of forces = mass × acceleration. If a known force was applied to an object with a known mass, how would you predict that object's acceleration?

Planets with larger orbital radii have longer orbital periods only because they have a longer distance to travel in each orbit.

Newton showed that Kepler's laws are _ _.

Newton's version of Kepler's third law states: In this equation, what does a represent?

Which of the following scenarios involves energy that we would typically calculate with Einstein's formula E = mc2?

The planets never travel in a straight line as they orbit the Sun. According to Newton's second law of motion, this must mean that .

Suppose an object is moving in a straight line at 50 mi/hr. According to Newton's first law of motion, the object will