ESCAPE VELOCITIES
Keywords: escape velocity
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What does escape velocity mean? [1]
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Let's try and break this up into two. The word "escape" means to break free from something and "velocity" is how fast an object is moving or the speed of the object. If we were to put this together, the escape velocity is simply the speed needed to completely leave a planet, breaking free from the force of gravity pulling it to that planet.
escape + velocity = escape velocity
"to break free"
"speed of an object in a certain direction"
"speed/velocity of an object to leave a planet, completely breaking free from the gravitational force pulling object to that planet"
Real Life Example - Using a Ball [2]
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Say if you throw a ball up into the sky while standing on the ground, the ball will go up a certain distance before it falls back down. Now this time, imagine if you throw the ball so fast that it never falls back down but rather keeps moving upwards even reaching further into space. We say that the speed you threw that ball is called the escape velocity.
Throwing a ball into the air. It'll move upwards
After some time, the ball will reach a certain height, and then fall back down.
So if you want to launch the ball into outer space, you must throw it at its escape velocity so it breaks away from Earth's gravitational pull
How fast would an object have to travel if it had to completely leave Earth?
If we wanted to send an object completely into space from Earth, its escape velocity at the surface of the Earth would be 11.2 km/s (kilometres per second) [2]. (with the assumption that there is no air resistance)
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To see how this really works - Have a go at our escape velocity simulation. What happens when the speed of the rocket is less than the escape velocity at the surface of the Earth?
Escape Velocity - Simulation
This simulation asks you to fly a rocket. You are in control over how fast you wish to fly.
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What happens when you fly at 11 km/s? Can you explain why that happens?
But, your velocity will determine how far your rocket will travel