# How to calculate time with delta-v and velocity?

• B
• alberto91
In summary, the conversation discusses the use of dimensional analysis and the incorrect use of units in an equation. The person asking the question is trying to use the equation t=d/v, but is using 1 m/s as a measure of distance instead of velocity. The expert suggests using the equation ##t_{needed} = v_{needed}/a## to find the time needed to reach a specific velocity, but notes that this assumes constant acceleration from zero and asks for more context about the acceleration being used.
alberto91
Is this correct?

Why the time is minutes instead of seconds?

Thanks!

Delta2
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.

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)?

## 1. How do I calculate time with delta-v and velocity?

To calculate time with delta-v and velocity, you can use the formula t = Δv/v, where t is the time, Δv is the change in velocity, and v is the velocity. This formula assumes that the acceleration is constant.

## 2. What is delta-v and how does it relate to time and velocity?

Delta-v, also known as change in velocity, is a measure of the difference between the initial and final velocity of an object. It is directly related to time and velocity through the equation t = Δv/v. This means that the greater the delta-v, the longer it will take for an object to reach a certain velocity.

## 3. Can I use delta-v and velocity to calculate time for any type of motion?

No, the formula t = Δv/v only applies to situations where the acceleration is constant. If the acceleration is not constant, you will need to use more complex equations to calculate time.

## 4. How does the mass of an object affect the calculation of time with delta-v and velocity?

The mass of an object does not directly affect the calculation of time with delta-v and velocity. However, it does affect the amount of force required to change the velocity, which in turn affects the acceleration and ultimately the time it takes to reach a certain velocity.

## 5. Can I use delta-v and velocity to calculate time in space travel?

Yes, delta-v and velocity can be used to calculate time in space travel. In fact, this is a common method used by scientists and engineers to plan and execute space missions. However, the calculations may become more complex due to factors such as gravity and the changing mass of the spacecraft as fuel is consumed.

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