Classical mechanicsLesson 2 of 2 in the course Gravitation

Relativistic Gravity, Black Holes, and Dark Matter Evidence

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

Save course
Lesson progress
0 / 5

Your progress is kept in this browser only.Sign up to save it

Summary

This lesson introduces why Newton’s highly successful account of gravity needed to be reconsidered and explains Einstein’s principle of equivalence.

Newton’s law of universal gravitation accurately describes many motions in the solar system. It has helped scientists predict the paths of planets, asteroids, and spacecraft. Yet Newton’s theory does not explain how gravity is transmitted from one object to another. Its traditional interpretation allows a change in one mass to affect another instantly, even across empty space. This is called action at a distance.

All flashcards

Action at a distance
Influence between objects without physical contact; Newtonian gravity was traditionally interpreted as acting instantaneously.
Principle of equivalence
In a sufficiently small region, a uniform gravitational field and uniform acceleration have indistinguishable effects.
Free fall and apparent weightlessness
A freely falling person and their surroundings accelerate together, so there is no usual supporting force.
Gravitational time dilation
Clocks deeper in a gravitational field run more slowly relative to clocks farther away.
Schwarzschild radius
For a nonrotating, uncharged mass, the radius of its event horizon is Rs=2GMc2R_s=\frac{2GM}{c^2}.

Quiz questions

  1. How does general relativity describe the effect of mass and energy on gravity?Answer: Mass and energy curve space-time, influencing the paths objects follow.
  2. What did general relativity explain about Mercury’s perihelion?Answer: It accounts for the small residual advance not explained by Newtonian calculations.
  3. How do clocks at different gravitational potentials compare?Answer: A clock deeper in a gravitational field runs more slowly than one farther away.
  4. For a nonrotating, uncharged mass MM, which expression gives the Schwarzschild radius?Answer: Rs=2GMc2R_s=\frac{2GM}{c^2}
  5. What is the event horizon of a black hole?Answer: A boundary beyond which nothing can escape to the distant outside universe.

Based on University Physics Volume 1 by William Moebs, Samuel J. Ling, Jeff Sanny (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.

More in Classical mechanics

All Classical mechanics lessons
Classical mechanicsNewton’s Third Law, Motion, and System Boundaries5 flashcards · 5 quiz questions · 4 gamesPlay free →Classical mechanicsSimple Harmonic Motion: Spring Oscillators, Phase, and Equilibrium5 flashcards · 5 quiz questions · 4 gamesPlay free →Classical mechanicsAngular Kinematics and Acceleration in Circular Motion5 flashcards · 5 quiz questions · 4 gamesPlay free →Classical mechanicsGravitational Fields, Weight, Rotation, and Gravity Inside Spheres5 flashcards · 5 quiz questions · 4 gamesPlay free →Classical mechanicsFree-Body Diagrams: Components, Contact Forces, and Constraints5 flashcards · 5 quiz questions · 4 gamesPlay free →Classical mechanicsCommon Forces and Fictitious Forces in Newtonian Mechanics5 flashcards · 5 quiz questions · 4 gamesPlay free →