Explanation:
F net of sled = Tension force by rope - Kinetic friction between ground.
F normal of sled = mg = (67kg)(9.81kg/m^2) = 657.27N.
Kinetic friction = 0.18 (I cannot see the value) * Normal force of sled = 0.18 * 657.27N = 118.31N
So F net of sled = 800N - 118.31N = 681.69N.
(I cannot see what the question is asking for, please check on your own!)
Answer:
Black Hole
Explanation:
A black hole is a very dense and massive stellar object, which has a field of gravity so large that not even light can escape it.
Since it does not emit light, <u>we cannot see them directly</u>, hence the name of black hole.
So in this case,<u> if the object has a mass of 8 solar masses that is enough to form a black hole</u>, and <u>also cannot be seen</u>, all of this indicates that the object we are talking about is a black hole.
It should be mentioned that although these objects do not emit light, because it cannot escape due to the immense force of gravity, black holes can be detected by a type of radiation emitted on their event horizon due to quantum effects called Hawking radiation .
Dementia is a brain disease that causes a decline in memory and cognitive functioning at a much more rapid rate that is expected due to normal aging. There is no known cure and no set age that dementia can occur, but roughly 10% of people will develop it at some point in their lives. It typically affects older people and about 50% of people over 85 have dementia.
Before Pluto was discovered, it was predicted. Astronomers had observed that massive objects can affect the orbits of its neighbors, and, after seeing deviations in the orbits of Uranus and Neptune, assumed something substantial existed beyond their orbits.
When Pluto was spotted, it was thought to be the predicted object and was identified as a ninth planet.
A few decades later, astronomers started discovering more and more objects around other stars and didn’t know whether to call them planets or not. There appeared to be a need to define what a planet means, and that led to what some people consider Pluto’s demotion to a dwarf planet.
The International Astronomical Union decided that full-sized planets must orbit the sun, have a round shape, and have cleared their orbits of other objects. Pluto fulfills the first two criteria, but not the third.
It still goes around the sun, it’s round enough, it’s got moons, and behaves like a planet, but the idea is that Pluto did not form the same way as the rest of the planets. Pluto’s orbit is both eccentric and inclined more than the rest of the planets by about 17 degrees. That’s suggests something is different about this object.
This debate about whether to call it a planet or not is silly, because it doesn’t matter to Pluto what you call it. It is an interesting object, goes around the sun, and shows geology and an atmosphere.
There’s a tendency to define objects based on what they are now, but nothing is constant in the universe. There are some issues with the nomenclature, and a definition today may not apply to the same object tomorrow.
Answer:
The minimum total speed is 11.2km/s
Explanation:
We are been asked to find the escape velocity.
Escape velocity is defined as the minimum initial velocity that will take a body(projectile)away above the surface of a planet(earth) when it's projected vertically upwards.
The formula to calculate the escape velocity is Ve = √2gR
For the earth g = 9.8m/s2 , R = 6.4*10^6
Substituting into the equation Ve = √2*9.8*6.4*10^6 = 11.2*10^3m/s
=11.2km/s
