How to tell which function has distance proportional to time?

In summary, the conversation discusses the concept of distance being proportional to time and the graphical representations of this relationship. The conclusion is that for a relationship to be directly proportional, the equation must be in the form of y = kx, where k is a constant. Curve A and B show distance as a linear function of time, while Curve C does not pass through the origin and is not a straight line. The expression "proportional to time" excludes other powers of time such as time squared or time to the power of 1/n. Additionally, the curve function does not have distance proportionate to time because on the right hand side, distance appears to be increasing while time remains constant.
  • #1
gurpalc
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Homework Statement



http://imgur.com/aYCc9

also in attachment

Homework Equations



n/a

The Attempt at a Solution



I'm not sure how to tell when distance is proportional to time. My guess is it would be graphs a and b because they're both straight lines and when time increases, distance increases a set amount as well.

Also can you explain why the curve function does not have distance proportionate to time?
 

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  • #2
a) Curve A and B show distance as a linear function of time.

b) I believe only curve A shows distance proportional to time. Curve B does not pass through the origin. Curve C isn't straight.

Regarding Curve C. The expression "in proportion" hints at constant ratio. So for it to be directly proportional the equation must be of the form

y/x = k
or
y = kx

where k is a constant called the constant of proportionality. K can be -ve or +ve.
 
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  • #3
Also can you explain why the curve function does not have distance proportionate to time?

See above. In addition, for this particular example only, on the right hand side the distance appears to be increasing while time remains constant. Putting aside the practicalities of achieving infinite velocity it shows that in this region of the curve distance appears to be independant of time.
 
  • #4
The expression "proportional to time" is normally taken to mean "proportional to time1 and excludes other powers such as timen, time1/n etc
 
  • #5
Thanks everyone for the replies. I got it now.
 

Related to How to tell which function has distance proportional to time?

1. How do you determine if a function has distance proportional to time?

The easiest way to determine if a function has distance proportional to time is to graph it. If the graph is a straight line passing through the origin, then the function has distance proportional to time. This means that as time increases, distance also increases at a constant rate.

2. What is the mathematical representation of a function with distance proportional to time?

A function with distance proportional to time can be represented as d = kt, where d is the distance, t is the time, and k is the constant of proportionality. This means that the distance is directly proportional to time, and the constant k represents the rate at which distance changes with time.

3. Are there any real-life examples of functions with distance proportional to time?

Yes, there are many real-life examples of functions with distance proportional to time. One common example is the distance traveled by a car at a constant speed. As time increases, the distance traveled also increases at a constant rate. Another example is the distance traveled by a person walking at a constant speed.

4. How can we use a function with distance proportional to time in our daily lives?

Functions with distance proportional to time can be used in various ways in our daily lives. For example, they can be used to calculate the time it takes to travel a certain distance at a constant speed, or to determine the speed at which an object is moving based on its distance and time values. They can also be used in physics to analyze the motion of objects.

5. Can a function have distance proportional to time in some cases but not in others?

Yes, a function can have distance proportional to time in some cases but not in others. This depends on the specific situation or context in which the function is being used. For example, if a car is accelerating or decelerating, the function will not have distance proportional to time. However, if the car is traveling at a constant speed, the function will have distance proportional to time.

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