Answer to Question 1
The escape velocity of a celestial object is the speed that an object on its surface needs to escape the gravitational field. A black hole is so dense that the escape velocity is greater than the speed of light, so light cannot escape the black hole; hence, the term black.
Answer to Question 2
It became known as the Copernican Revolution because it was not just the adoption of a new idea but a total change in the way astronomers, and, in fact, all of humanity, thought about Earth and its place in the Universe. In fact, our modern use of the words revolution and revolutionary to describe philosophical, political, and social upheavals comes from the title of Copernicus's book, De Revolutionibus, which means On Revolutions.
The pancreas. This organ sits just below the stomach and is both an exocrine and an endocrine gland.
Cardiac catheterization. Insertion of a tube called a catheter through a blood vessel. In this examp
Bergmann’s and Allen’s rules expressed in two rabbit species. (a) A snowshoe hare. (b) A desert-livi
Snap-ring pliers are also called lock-ring pliers, and they are designed to remove internal and ...
Cancer cells can move to new locations in the body, a process called metastasis
For the circuit in Figure 1, assume ideal diodes. The peak inverse voltage is approximately