# The rocket launch and changing gravity

• marco12345a
In summary, the conversation discusses the effects of Earth's rotation and gravity on a rocket's launch and orbit. It also touches on the concept of changing mass due to fuel consumption and the calculation of energy needed for a rocket to reach escape velocity. The participants also mention the changing gravity at different altitudes and the use of equations to solve for weight and gravitational acceleration.
marco12345a
When a rocket is launched, it starts not with velocity zero, but with the rotation velocity which the Earth gives it. Thus if a rocket is launched eastward, it requires a smaller boost (and if westward, a larger one) to achieve orbit. with a latitude of 31.1 degrees, cos(31degrees) 24902/24 = 393.11 ms/s

To escape velocity on Earth = (2G Mearth / r earth) = 11200ms-1
So the total velocity that needed for the rocket = 11200 - 393.11= 10806.99ms-1

I am trying to find the total energy that is needed for the rocket of 1000kg to escape velocity

i used the question
m = 1000 x 9.8 N

E= 1/2 m^2
= 5.84 X 10^10 J

my question is : as the further you are away from earth, there will be less gravity. So if i use that equation, would that be accurate assume there is no air friction and the mass of the rocket doesn't change due to the loss of fuel

That would be close enough! But the problem is that the accuracy falls as u go on neglecting decreasing mass due to consumption of fuel.

should i use the equation of E= 1/2 m^2 ?

marco12345a said:
should i use the equation of E= 1/2 m^2 ?

If u r calculating energy, then of course it'll do. note that, E=1/2mv^2=GMm/r

but doesn't the changing gravity affect the m ?

marco12345a said:
but doesn't the changing gravity affect the m ?

Yes but if u really want to solve it u will hav to take an average of that.

marco12345a said:
but doesn't the changing gravity affect the m ?

more than that...changing mass is a prob.

for example if a rocket is 1000 kg on Earth , what would the gravity be when it is at 300m

marco12345a said:
for example if a rocket is 1000 kg on Earth , what would the gravity be when it is at 300m
If u r dealing with mass, it would be 1000Kg itself. if u r dealing about wight, itll bcom
W=mg
=1000*g
g= gravitational acceleration at 300mts
u manipulate it...
g=w/m
=w/1000
ul hav to know its weight there.

how do you find the changing gravity ?

the gravity doesn't change preferentially at 300mts
observ: g=9.806 in 0mts
g=9.803at 1000mts

ok bye..

okay thank you very much

## What is a rocket launch?

A rocket launch is the process of sending a spacecraft or rocket into outer space. This is achieved by using powerful engines to propel the rocket off the ground and through the Earth's atmosphere.

## How does a rocket launch work?

A rocket launch works by using the force of gravity to accelerate the rocket upwards. The rocket's engines create thrust, which pushes it against the force of gravity. As the rocket moves higher and higher, the force of gravity decreases, allowing the rocket to reach higher altitudes.

## What is gravity?

Gravity is the natural force that attracts objects with mass towards each other. It is responsible for keeping the planets in orbit around the sun and for keeping us grounded on Earth. Gravity also plays a crucial role in rocket launches and space exploration.

## How does gravity change during a rocket launch?

During a rocket launch, gravity gradually decreases as the rocket moves further away from the Earth's surface. This is because gravity is directly proportional to the distance between two objects - the further apart they are, the weaker the force of gravity between them.

## What are the effects of changing gravity during a rocket launch?

The effects of changing gravity during a rocket launch can include changes in the weight and acceleration of the rocket, as well as changes in the trajectory and speed of the launch. These changes must be carefully calculated and accounted for in order to ensure a successful launch and safe journey into space.

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