Kinematics - how do u find distance travelled

  • Thread starter meee
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In summary, when calculating the distance traveled in a specific time frame, it is important to use the integral of the absolute value of velocity to account for any changes in direction. This can be done by adding up the y values of a displacement/time graph or by using the integral of the modulus of the velocity function.
  • #1
meee
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ok. so i have x(t) = something and v(t) = something

i know x will give me the displacement for a set time

say if i wanted the distance traveled in the first ten seconds, i know i can use the definite integral of velocity.

Is there any easier way? like using the displacement equation?
 
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  • #2
Actually you can't use the definite integral of velocity-you have to use the definite integral of the absolute value of velocity or else you'd be measuring displacement and not distance. You don't want the distance traveled to start decreasing just because the velocity becomes negative.

Since it is in 1 dimension, if it never turns around, then its distance traveled after 10 seconds is the absolute value of its position after 10 seconds. If it does turn around and double back on its path then what can you say about the distance?
 
  • #3
then it would be double!

lol ok... so if i have like a parabola graph of displacement/time i can just add up from the y values of start to max/mins and end point etc.
 
  • #4
As orthodontist said, you must use the integral of the modulus of your function of velocity;

[tex]\int^{10}_{0} \left| v(t) \right| dt [/tex]

The process is quite laborious and not one of my favourite things to do, have you solved modulus functions before?
meee said:
so if i have like a parabola graph of displacement/time i can just add up from the y values of start to max/mins and end point etc.
Yes, that would work :smile: (I think)
 
  • #5
sweet thanks guys
yeah I've done modulus functions
 

What is kinematics?

Kinematics is the branch of physics that studies the motion of objects without considering the forces that cause the motion.

How do you calculate distance travelled?

The distance travelled is equal to the product of the average velocity and the time taken. This can be represented by the equation: distance = average velocity x time.

What is average velocity?

Average velocity is the total displacement divided by the total time taken. It is a measure of the overall rate of an object's motion.

Can the distance travelled be negative?

Yes, the distance travelled can be negative if the object moves in the opposite direction of the initial position. However, distance is a scalar quantity and is always positive, while displacement is a vector quantity and can be negative.

What is the difference between distance and displacement?

Distance is the total length of the path travelled by an object, while displacement is the straight-line distance between the initial and final position of an object. Displacement takes into account the direction of motion, while distance does not.

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