High School How to calculate time with delta-v and velocity?

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SUMMARY

The discussion focuses on calculating time using delta-v (dv) and velocity in the context of physics, specifically through the equation t = d/v. It highlights the importance of using correct units, emphasizing that velocity must be in meters per second (m/s) and distance in meters. The correct approach involves using the relationship between acceleration and time, expressed as dv/dt = a, leading to the integration of the equations to derive t_needed = v_needed/a. The conversation underscores the necessity of constant acceleration for accurate calculations.

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  • Understanding of basic physics concepts, specifically acceleration and velocity.
  • Familiarity with dimensional analysis in physics.
  • Knowledge of calculus, particularly integration techniques.
  • Ability to manipulate and convert units of measurement.
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  • Study the principles of constant acceleration in physics.
  • Learn about dimensional analysis and its applications in physics calculations.
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alberto91
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Is this correct?

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Why the time is minutes instead of seconds?

Thanks!
 
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By dimensional analysis your t has no units.
 
WWGD said:
By dimensional analysis your t has no units.

And how can I calculate that equation?
 
What I mean is you're dividing two expressions with m/s as units, which cancel out. This tells you you're doing something wrong somewhere. I guess you want to use t=d/v? Then d is given in meters ( or another unit of distance) . In your case you used 1 m/s , which is not a measure of distance.
 
WWGD said:
What I mean is you're dividing two expressions with m/s as units, which cancel out. This tells you you're doing something wrong somewhere. I guess you want to use t=d/v? Then d is given in meters ( or another unit of distance) . In your case you used 1 m/s , which is not a measure of distance.

Thanks for your answer.

I want to use delta-vee (dv)
 
To find the time you need a relationship between velocity and time such as the definition of acceleration:

##\frac{dv}{dt}=a##

Then separate and integrate:

##dv=adt \rightarrow \int_{0}^{v_{needed}} dv = \int_{0}^{t_{needed}}a dt##

This gives

##v_{needed} = at_{needed}##

So to find the time needed to get to the needed velocity, simply divide.

##t_{needed} = v_{needed}/a##

Note that this assumes constant acceleration from zero. So it seems the solution you showed has the wrong units for acceleration.
 
Last edited:
There is context missing. Do you have a constant acceleration? If yes, what is its value? Maybe 0.2636 m/(s*min)?
 

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