Two satellites A and B of the same mass are going around Earth in concentric orbits. The distance of...
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Two satellites A and B of the same mass are going around Earth in concentric orbits. The distance of satellite B from Earth’s center is twice that of satellite
Two satellites A and B of the same mass are going around Earth
in concentric orbits. The distance of satellite B from Earths
center is twice that of satellite A. What is the ratio of the
centripetal force acting on B to that acting on A ? 1. 1/8 2. 1/4
3. 1/2 4. 12 5. 1
Slide 2
Two satellites A and B of the same mass are going around Earth
in concentric orbits. The distance of satellite B from Earths
center is twice that of satellite A. What is the ratio of the
tangential speed of B to that of A ? 1. 12 2. 12 3. 1 4. 2 5.
2
Slide 3
Suppose Earth had no atmosphere and a ball were fired from the
top of Mt. Everest in a direction tangent to the ground. If the
initial speed were high enough to cause the ball to travel in a
circular trajectory around Earth, the balls acceleration would 1.
be much less than g (because the ball doesnt fall to the ground).
2. be approximately g. 3. depend on the balls speed.
Slide 4
The Moon does not fall to Earth because 1. It is in Earths
gravitational field. 2. The net force on it is zero. 3. It is
beyond the main pull of Earths gravity. 4. It is being pulled by
the Sun and planets as well as by Earth. 5. all of the above 6.
none of the above
Slide 5
Black Holes What is a black hole? Gravitational well with
extremely high gravitational forces. Singularity Event Horizon
(Point of no return) RsRs Creation of a black hole: 1.Massive star
explodes Supernova 2.Mass that does not travel far enough gets
pulled back and the mass collapses under gravitational forces to
form one of the following: a)White Dwarf M < 1.4 M sun b)Neutron
Star M > 1.4 M sun c)Black Hole M > 3 M sun For a black hole
the mass is compacted into a single point called a singularity.
Ideally this point would have zero volume and therefore infinite
density. Everything that enters a black hole (passes the event
horizon) is pulled into the singularity, including light! R s
Schwartzchild radius Extremely dense star (R ~ 10 km) 1 teaspoon
weighs 5 billion tons!
Slide 6
The black hole can emits high energy electromagnetic radiation,
as shown in the illustration below. This electromagnetic radiation
is not in the visible spectrum. A star loses mass to a black hole.
This is the result of a single star of a binary pair collapsing
into a black hole, or possibly a single star exploding and creating
a black hole and another star. An astronaut entering a black hole.
The gravitational forces are so strong that the gravitational force
at the astronauts head is stronger than the gravitational force at
his feet. This causes the stretching and eventually the astronaut
would be torn apart.