If I throw in space an object with a constant acceleration, will the object keep it? And if it keeps the acceleration, will it get the light's speed one day?
I can answer the question in two different ways:The object is thrown in space- there are no more forces acting on it so it will ahve zero acceleration and will continue moving in a straight line at constant speed. ( A classic example of Newton’s first law)The object is launched into space with some type of motor which is able to supply a constant acceleration. If this is what the question means then there is a problem.a) The motor cpould provide a constant force which produces constant acceleration until the speeed of light is approached. The mass starts to increase so the acceleration dropps. AS you approach c the mass approacheds being infinite so the acceleration drops to zero. So you never quite get to the speed of light.b) The motor does provide constant acceleration. In this case, as the object approaches the speed of light, the motor would be required to produce an infinitely large force to maintain that acceleration - the motor will not be able to produce an infinitely large force.Whatever the question was meant to ask, it doesn’y matter, the object wont reach the speed of light.
What is the smallest man-made object, intentionally launched into space?
I'm thinking Sputnik 1 has to be a contender for individually launched into space while also being the very first man-made object in space. It weighed 83.6 kg/184.3 pounds, it's diameter was 585 mm/23 inches and it stayed in orbit for 92 days. But, it only transmitted a simple Morse Code type signal for 22 days and it shook the world!
Is there a gun in the world that can launch a projectile into orbit?
Yes and no.The first problem you will encounter is getting the object towards orbital heights. If you fire something at high speed, it will slow down because of drag, unless it's in a vacuum without any other forces working on the object. Secondly, shooting something upwards will slow it down because part of its kinetic energy is converted into potential energy in the form of altitude(I don't know if I formulated it in the correct way, English isn't my native language, but I think you get the point). So you are already losing a lot of your velocity because of these two forces, that means that by the time the object is at high altitude, your velocity might be to low to escape earth's gravity.But lets say you do get something into space. When a satellite for example is in orbit, it will use its thrusters to maintain its orbit, but if you shoot something into space without thrusters, it will probably either escape orbit or it will burn up while it's crashing towards earth.So it might be possible, but you will need an object which can correct its orbit and survive the launch, and a huge gun.P.S. Sorry if my English is too bad, but I'm only 17 and English isn't my native language.
Will an object, thrown in space, accelerate or travel at a constant speed?
Newton's First Law states that an object will remain at rest or in uniform motion in a straight line unless acted upon by an external force.If u thrown an object into the space, it will continue moving in its straight path with the same velocity of ur initial throw. And it maintains constant velocity until some external forces (either moving or stable solid, liquid, gas particles/objects) changes its direction or speed.And it will never accelerate until some external forces accelerate it. Even if the external forces stop its acceleration, the object will move on with the velocity of external applied force (as the last moment it released).By practically, the object will slows down by the space junks and other particles. Or it may increases its speed by the gravitational field of our galaxy. That's y astronauts r tied with their space ship with a belt to avoid getting sucked up by space.Gravity everywhere…
Mass of an object does not affect the free fall acceleration?
Okay, so we all know that the gravitational pull of earth on any object is 9.8 m/s^2. However, I am not fully convinced that the mass has nothing to do with it. For example, if an object the size of the moon, or bigger were to be "dropped" towards the earth, then it wouldn't really get closer to earth at a rate of 9.8 m/s^2. What I think is that every object in earth is negligible compared to the size of the earth; therefore, they all fall at with this acceleration. Correct me if I am wrong.
How to measure distance in space?
Your question is really good. But, I'll object your statement "if some thing happens in universe,immideatly telescopes finding it". No!!! Any happening in the universe will be propagated with the speed of light. For e.g. If in our solar system, we know that light takes around 8 min to reach from sun to earth. so imagine a condition If somehow you take off sun from solar system, it will take 8 mins to let you know that sun has disappeared even though you are looking at sun (through a proper filter) continuously. Astronomical objects are so distant that whatever object you see today, light has emerged from those objects 100's of years back... Its not possible to communicate any incident faster than the speed of light. This was highlighted in Special theory of relativity by Einstein. Now if your question is how to measure a distance between object just by looking at a light coming from it, it may done by looking at half-life time of photons. Somebody technical at particle physics may give a detail answer on this.
Why does a rocket need to get to escape velocity to get into space?
The answer is that a rocket doesn’t need to get to escape velocity to reach space. Escape velocity (at the Earth’s surface) is that speed which is required to completely overcome Earth’s gravitational field. You need to reach escape velocity if (say) you want to travel to Mars, but not if you just want to get to the International Space Station.Note that the escape velocity is lower the higher a rocket gets above the Earth’s surface. No rocket will instantly hit escape velocity as it is launched. It will rather speed over time, and by the time it reaches escape velocity that might be somewhat lower than the escape velocity at the Earth’s surface.Space is generally considered to start at about 100km above the Earth’s surface (although that’s a rather arbitrary definition as the, by then, very thin atmosphere continues further). The minimum requirement of a rocket to be considered to have reached space by that definition would be to reach that altitude. The WW II V2 rocket reached almost that altitude and its peak speed was less than 6,000 m/s, or only about 14% of escape velocity.The next step up is to go fast enough to go into orbit, and that’s what is called orbital velocity. If you take the first artificial satellite, Sputnik 1, that had an orbital speed of about 18,000 km/hr, or rather less than half escape velocity.Satellites travelling in higher orbit (such as the geostationary ones occupied by satellite TV broadcasters) have a lower orbital speed, but it may be necessary (depending exactly on how long the “burns” last and the number of stages) for the rocket to achieve a much higher speed than the eventual orbital speed.NB, I should add and answer to your text as well. You are quite right that, in theory, a rocket which could maintain a constant 1 km/s (which is about the maximum speed of a V2 rocket) would eventually break free of Earth’s gravitational pull (and that would be at the altitude where the escape velocity is 1 km/s). However, it’s not practical to do it that way and that is because the rocket will have to burn fuel for the entire time which, in its turn, means it will be supporting the useless weight of the fuel and not the payload. It’s more efficient to burn off that fuel much faster and accelerate to a higher speed to avoid wasting energy supporting all that weight. There are other tricks, such as using multi-stage rockets to avoid carrying too much “dead weight” into orbit.
According to Newton's first law of motion, a rocket does not need fuel to travel in space once it is given an acceleration, as there are no forces in space blocking its motion. Why is it not true?
It is true that an object in motion will remain in motion unless acted upon by an outside force.It is not true there are no such forces in space. In Newtonian terms, gravity is a force.The force of gravity is equivalent to the gravitational constant multiplied by a fraction made up of the masses of the two bodies in question and the distance between those two bodies, squared.So, let's take a look at an example for a spaceship leaving Earth. For simplicity, we will make it a very small spaceship with a mass of exactly 1 kilogram. The mass of the Earth is 5.972E24 kg. G is 6.67E-11 m^3/kgs^2. The radius of Earth is 6371km.We can see that for fixed masses for our spaceship and for Earth, gravity is a force that depends only on distance. As the distance grows, the force gets smaller, but it only truly reaches zero at infinity. Here's a graph of the force.Another way to visualize gravity is as a well. Gravity is the curvature of space by mass. The greater the mass, the greater the curvature. In order to get away from Earth, our spaceship must climb out of that well. As it gets farther from the mass, the well is less steep, and climbing is easier. But it is still climbing.Now it gets a little more complex, because we have to account for other masses, too. The Earth's gravity well is within the gravity well of the Sun.So, moving away from the Earth requires force and moving away from the Sun requires force.But, that does not mean we have to perpetually be creating a force. This is where the concept of escape velocity comes into play.When a spacecraft is heading outwards, away from the Earth, and the engines are not firing, the only force present is gravity. That gravity will pull at the spaceship, slowing it down, little by little. But, the farther the spaceship gets from Earth, the smaller that deceleration is. Escape velocity is the speed at which if we added up all of the deceleration from the Earth, it will only make the spaceship velocity reach zero at a distance of infinity - meaning the spaceship has successfully escaped Earth and doesn't need to fire its engines again.