Can you allways use speed = distance /time relation

In summary, when trying to find the time taken given the velocity and distance traveled, the speed = distance/time relationship can be used, even if the velocity is not constant. However, if the motion is not constant, the process must be broken into parts with constant velocity, and the time for each part must be calculated separately before adding them together to find the total time. In some cases, calculus may need to be used to accurately calculate the time.
  • #1
Alem2000
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My question is when you know your velocity and the distance traveled...can you allways use speed =distance /time relation to find time..? Because it seems to only work on some occasion...i know this sounds like a stupid question but i just don't get it. Or does your velocity have to be conastant to be able to use this relationship?
 
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  • #2
displacement = velocity * time... only when velocity is constant.
 
  • #3
time=dist./speed

even if the velocity is not constant, you can find the time taken.

Do the following.
Break up the whole motion into parts. And those parts should be such that the velocity is constant in them. Now, for each part, calculate the time as

(distance traveled in that part) / (speed in that part, which is constant)

so you see, now you can add up all of the time intervals to get the whole time.

If the numebr of intervals becomes way too large, then you need to use calculus.

spacetime
www.geocities.com/physics_all/index.html
 

Related to Can you allways use speed = distance /time relation

1. Can speed always be calculated using the distance/time relation?

While the distance/time relation (speed = distance / time) is a fundamental equation in physics, it can only be used to calculate speed if the distance and time values are known. If either of these values is missing or unknown, the equation cannot be used.

2. What are some common applications of the distance/time relation?

The distance/time relation is used in various fields such as physics, engineering, and transportation. It is commonly used to calculate the speed of moving objects such as vehicles, projectiles, and fluids. It is also used in determining the velocity of sound and light, as well as in the study of motion and energy.

3. Are there any limitations to using the distance/time relation?

Yes, there are limitations to using the distance/time relation. One limitation is that it assumes constant speed, which may not always be the case in real-life situations. It also does not take into account external factors such as air resistance, friction, and acceleration, which can affect the speed of an object.

4. Is the distance/time relation the only way to calculate speed?

No, there are other equations and methods for calculating speed depending on the specific situation. For example, the average speed can be calculated by dividing the total distance traveled by the total time taken. In cases where the speed is not constant, more complex equations such as the formula for average velocity (change in position / change in time) may be used.

5. Can the distance/time relation be used for all types of motion?

The distance/time relation can be used for any type of motion as long as the distance and time values are known. However, it is most commonly used for linear motion, where an object moves in a straight line at a constant speed. For other types of motion such as circular or accelerated motion, different equations and methods may be required to accurately calculate speed.

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