What was the acceleration of the rocket?

In summary: I will check my numbers more carefully next time.In summary, the rocket moved 240 km in 5 minutes while accelerating backwards at a constant rate. Using the equation r= ut + 1/2at^2, the acceleration can be calculated to be -0.133 m/s/s towards the star.
  • #1
fcb
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Homework Statement



A rocket moving towards Alpha Centuari at 1000ms^-1 fires its rockets, accelerating backwards at a constant rate for 5 minutes. During this 5 minutes, the rocket moved 240km close to the star. What was the acceleration?

Homework Equations



I have no idea what formula you should use
Maybe:
r= ut + 1/2at^2

The Attempt at a Solution



Hmm , i'll tell you my attempt , but srsly this question is hard

r = ut + 1/2at^2

r = 240 km = 240000 m
u = 1000m/s
t = 5 mins = 300s
a = ?

240000 = 1000 x 300 + 1/2 x a x (300)^2
240000 = 300000 + 45000a

= - 6000 = 45000a

a = -6000/45000

a = -0.133m/s/s towards the star ...
 
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  • #2
I think your answer is sound, except that your final result is out by a factor of ten. Maybe you should check the numbers in the last few lines of your calculation.

In future, you might find it easier to move the symbols around first and then leave putting the numbers in until the very end. You could take the equation that you started with and rearrange it to get a = ... and THEN sub in the values from the question.
 
  • #3
Sorry, with the equation, I don't seem to know where I went wrong. I think it's the right formula but
 
  • #4
I am so confused ?? looking at that equation does my head in.
 
  • #5
Yes, the formula is right, and all of your working is fine until you get to the last few lines

240000 = 300000 + 45000a

= - 6000 = 45000a

Check the numbers and you should find that you're missing a zero somewhere.
 
  • #6
Ohh I see what you did. Thanks
 

1. What is acceleration?

Acceleration is the rate at which an object's velocity changes over time. It is measured in units of distance per time squared, such as meters per second squared.

2. How is acceleration calculated?

Acceleration can be calculated by dividing the change in velocity by the change in time. The formula for acceleration is: a = (vf - vi) / t, where a is acceleration, vf is final velocity, vi is initial velocity, and t is time.

3. What factors affect the acceleration of a rocket?

The acceleration of a rocket can be affected by several factors, including the mass of the rocket, the force of the rocket's propulsion, and the resistance of the air or other medium it is traveling through.

4. How does acceleration impact the motion of a rocket?

Acceleration is a key factor in determining the motion of a rocket. A higher acceleration will result in a faster change in velocity, leading to a greater speed and potentially higher altitude for the rocket. On the other hand, a lower acceleration may result in a slower, more controlled flight.

5. Can the acceleration of a rocket change during flight?

Yes, the acceleration of a rocket can change during its flight. This can happen if the force of propulsion changes, if the mass of the rocket changes, or if it encounters different levels of air resistance or gravity. It is important for scientists and engineers to carefully calculate and monitor the acceleration of a rocket to ensure a successful flight.

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