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Sati [7]
3 years ago
9

Why might exposing astronauts to weightlessness be harmful?

Physics
1 answer:
love history [14]3 years ago
5 0
The body doesn't have to work as hard when there's no gravity for it to work against, so it becomes accustomed to a much lower work load on every level. It leads to lower bone mass and weaker muscles, including the heart, leading to a drop in blood pressure that can eventually build up to create problems with cognitive function. After so long, minor accidents can lead to major, even life threatening problems. A simple bump that would do little more than leave a bruise on you and I can result in a broken femur bone or broken neck on an astronaut who has been exposed to a weightless environment for too long.

This is one of the several hurdles that must be overcome in order for a manned mission to Mars to succeed. Exposure to a weightless environment on the order of roughly two years for a manned Mars mission would be so degrading to the body that the rough, turbulent re-entry into Earth's atmosphere might prove to be too violent for an astronaut to survive.

The problem is bones.

On Earth, every time you do something with "impact" (like walking), there are microcracks in your bones. Calcium is used by the body to fix these cracks... and that is how the bones grow and become strong.

No weight = no impact = no cracks = no "repairs" being done by the body = the body gets rid of un-neede calcium and bones become brittle and weak.

There are some other operations in the body that require gravity as a "director", or resistance to movement as a driver of change (think of muscles in the legs, when there is no need to walk).

The organ themelves are (generally) OK since many things can work in any orientation.
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ON
mojhsa [17]

B. the distance the star is from Earth

Explanation:

The apparent magnitude of star is a function of its distance from the earth. It is one of the physical properties that is used to study a star.

The apparent magnitude of a star or other astronomical bodies is a measure of their brightness as seen from a location on the earth.

The apparent magnitude of a star depends on:

  • Distance of the star from the location on earth.
  • luminosity of the star
  • the particles along the part of the star and earth that cuts off the light the earth receives.

learn more:

Star luminosity brainly.com/question/9084808

#learnwithBrainly

5 0
3 years ago
What are the factor that affect the efficiency of a pulley​
alukav5142 [94]

Answer:

Tension in the chains - In a chain drive, technically, you have a closed-chain (which has no end) going around 2 pulley or gears; looking closely you have 2 parallel chains going in opposite direction. If kept in horizontal direction, the one below the other is the slack side and the other the tight side. The tension on the upper or tight side is more than the slack side. So you need to keep in mind to keep your chain drive tight so that there is no loss or rotation or lags.

Sizes of the pulley/gear - The chain will be warped around a pair of pulley or gear. The sizes of these pulley/gear will also determine the efficiency of the chain drive (consider one big and one small)

Number of pulley/gear - If the number of pulley/gear is more and chain wrapped on it with little complexity will result in decrease in efficiency because of extra tension.

Length of the chain drive - You cannot have much too long chain drive. It will make your slack side more heavy because the end are further away. You have to apply more power and possibilities of lag increases decreasing efficiency. In an ideal situation, this won't happen, but this world isn't ideal.

Friction between chains & pulley/gear - If you have studied gears (involving its teeth), you will come to know that there is friction offered on the two meeting surfaces.

Angle of contact - This would have been explained better with a diagram. Although, if you are familiar with the terms you won't have difficulty understanding. Angle of contact is the angle the chain forms with the pulley/gear at the point of contact with the center of the pulley. The angle of contact should not be too small, or else the things will be slippery.

Explanation:

8 0
3 years ago
People cut down a forest to bulid a housing development which of the following describes how this action will likely affect the
Ratling [72]

Answer:

It would mean less transpiration and the groundwater would start to make a landslide with no tree root to hold the earth in place

8 0
3 years ago
How does the force of gravity between two bodies change when the distance between them doubles?
polet [3.4K]

Answer:

If the distance is doubled, the force of gravity between the two bodies is one-fourth as strong as before

Explanation:

The force of gravity between two bodies depends on the mass and distance. But we will focus on distance since that's what the question asks

Therefore, the force of gravity decreases as distance between the bodies increases.

7 0
3 years ago
In an engine, an almost ideal gas is compressed adiabatically to half its volume. In doing so, 1850 J of work is done on the gas
hammer [34]

Answer:

The value of change in internal energy of the gas = + 1850 J

Explanation:

Work done on the gas (W) =  - 1850 J

Negative sign is due to work done on the system.

From the first law  we know that Q = Δ U + W ------------- (1)

Where Q = Heat transfer to the gas

Δ U = Change in internal energy of the gas

W = work done on the gas

Since it is adiabatic compression of the gas so heat transfer to the gas is zero.

⇒ Q = 0

So from equation (1)

⇒ Δ U = - W ----------------- (2)

⇒ W = - 1850 J (Given)

⇒ Δ U = - (- 1850)

⇒ Δ U = + 1850 J

This is the value of change in internal energy of the gas.

7 0
3 years ago
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