Answer:
Contact forces are forces that require the actual contact (touching) of two pieces of matter. There are a variety of contact forces. A very common one is friction. Anytime that two surfaces are in contact with one another, there is friction between the two surfaces. A field force is a force that works at a distance. No touching is required. Gravity is a good example of a field force, because it works whether or not an object is touching something or touching nothing at all.
Answer:
<em><u>Solid</u> is the state in which matter maintains a fixed volume and shape; liquid is the state in which matter adapts to the shape of its container but varies only slightly in volume; and gas is the state in which matter expands to occupy the volume and shape of its container.</em>
The conservation of the momentum allows to find the result of how the astronaut can return to the spacecraft is:
- Throwing the thruster away from the ship.
The momentum is defined as the product of the mass and the velocity of the body, for isolated systems the momentum is conserved. If we define the system as consisting of the astronaut and the evo propellant, this system is isolated and the internal forces become zero. Let's find the moment in two moments.
Initial instant. Astronaut and thrust together.
p₀ = 0
Final moment. The astronaut now the thruster in the opposite direction of the ship.
= m v + M v '
where m is propellant mass and M the astronaut mass.
As the moment is preserved.
0 = m v + M v ’
v ’=
We can see that the astronaut's speed is in the opposite direction to the propeller, that is, in the direction of the ship.
The magnitude of the velocity is given by the relationship between the masses.
In conclusion, using the conservation of the momentun we can find the result of how the astronaut can return to the ship is:
- Throwing the thruster away from the ship.
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Answer: 12.5 km/s
I don't really know how to explain this, but here is your answer.
Answer:
This equation is based on twin paradox - a phenomena where one of the twin travels to space at a speed close to speed of light and the other remains on earth. the twin from the space on return discovers that the one on earth age faster.
Solution:
= 10 years
v = 0.8c
c = speed of light in vacuum
The problem can be solved by time dilation equation:
(1)
where,
t = time observed from a different inertial frame
Now, using eqn (1), we get:

t = 16.67 years
The age of the twin on spaceship according to the one on earth = 25+16.67 =41.66 years