Question 1

A car is driving around a flat, unbanked curve of radius $$r at $$constant speed $$v. $$What provides the centripetal force necessary for the car to stay on the curve?

Accepted Answer

The static friction between the tires and the road

Question 2

Which of the following best describes the direction of the instantaneous velocity of an object in uniform circular motion?

Accepted Answer

It points tangent to the circle at every instant

Question 3

A satellite orbits the Earth at a constant altitude. Which statement best explains why it experiences apparent weightlessness?

Accepted Answer

Both the satellite and its contents are in free fall, so there is no normal force acting on them

Question 4

Which equation gives the magnitude of the centripetal acceleration for an object moving in a circle of radius $$r at $$speed $$v$$?

Accepted Answer

$$a_c = \frac{v^2$}{r}$$

Question 5

A ball is attached to a string and swung in a horizontal circle. If the string breaks, what path will the ball follow?

Accepted Answer

It will move in a straight line tangent to the circle at the point of release

Question 6

According to Newton’s law of universal gravitation, what happens to the gravitational force between two masses if the distance between them is doubled?

Accepted Answer

The force becomes one-fourth as strong

Question 7

Which of the following is the correct expression for Newton’s law of universal gravitation?

Accepted Answer

$$F = G \frac{m_1$ m_2$}{r^2$}$$

Question 8

A car is driving around a banked curve with no friction. At what speed will the car experience no sideways frictional force?

Accepted Answer

When the horizontal component of the normal force equals the required centripetal force

Question 9

Which of the following statements about friction on highway curves is correct?

Accepted Answer

Static friction is necessary for a car to safely navigate a flat curve

Question 10

A planet orbits the Sun in an elliptical path. According to Kepler’s second law, what is true about the area swept out by the line joining the planet and the Sun?

Accepted Answer

It sweeps out equal areas in equal times

Question 11

Which of the following is NOT a fundamental force recognized by modern physics?

Accepted Answer

Friction

Question 12

If the acceleration due to gravity at the surface of the Earth is $$g$$, the mass of the Earth $$M$$, and the radius of the Earth $$R$$, which equation relates these quantities?

Accepted Answer

$$g = G \frac{M}{R^2$}$$

Question 13

A satellite is launched into orbit around the Earth. What must its tangential speed be in order to remain in orbit at a given altitude?

Accepted Answer

$$v = \sqrt{G \frac{M}{r}}$$

Question 14

Which of the following best describes the forces experienced by objects in everyday life, excluding gravity?

Accepted Answer

They are due to electromagnetic forces acting at the atomic level

Question 15

A roller coaster moves through a loop-the-loop at constant speed. What is the direction of the centripetal acceleration at the top of the loop?

Accepted Answer

Toward the center of the loop

Question 16

If an object moves in a circle at varying speed, which type(s) of acceleration does it experience?

Accepted Answer

Both radial (centripetal) and tangential acceleration

Question 17

Kepler’s third law states that the ratio of the square of a planet’s orbital period $$T to $$the cube of its mean distance $$r$$ from the Sun is constant. Which equation expresses this law?

Accepted Answer

$$\frac{T^2$}{r^3$} = 	ext{constant}$$

Question 18

The Cavendish experiment was important because it allowed scientists to:

Accepted Answer

Measure the value of the gravitational constant $$G$$

Question 19

If the centripetal force acting on an object in uniform circular motion suddenly vanishes, what happens to the object?

Accepted Answer

It moves in a straight line tangent to the circle

Question 20

Which of the following is a real-world example of apparent weightlessness?

Accepted Answer

Astronauts floating inside the International Space Station

Circular Motion and Gravitation: Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard