Graph of a cart in motion using ticker tape

In summary, the conversation is about a lab exercise involving a cart attached to a string with a mass hanging off of it. The student has used ticker tape to track the motion of the cart and has calculated the velocity using v = d/t. However, the teacher has stated that the graph of velocity against time should resemble a root curve due to non-constant acceleration, but the student's graph is a straight line. The student is unsure of what a root curve should look like and is seeking clarification. The conversation also discusses the difference between velocity and displacement and how to properly calculate velocity from the ticker tape data.
  • #1

Homework Statement

Ok this is more of a problem I am having within a lab exercise. The scenario is this, I have a cart attached to a string that is attached to a mass of 100g hanging off the ground with a pulley.. So the cart is on a table, the string goes upwards, hooks around a pulley and goes downwards attached to a mass. I have ticker tape showing the motion of the cart then using time and displacement, I got velocity using v = d/t, and the data is as follows:
Time Speed
1 5.3
2 6
3 7.3
4 8.8
5 10.5
6 12
7 15
8 18
9 21

Homework Equations

v = d/t

The Attempt at a Solution

My problem is, that the teacher stated "It should be non-linear and resemble a root curve because the acceleration is not constant." However, when I graph this, the v-t graph is a straight line meaning that the acceleration is constant! To me, it makes sense that the acceleration is constant because there is a constant mass pulling on the cart with a constant force, the angle but my teacher says its not. Now I can easily change my data to whatever I want it to, my teacher has no problem with that, however I don't know what a root curve is supose to look like? is it like the graph of y = root(x) or is it more like y = 2^x?? Or maybe I am missing something and the data i have is right? i don't no, please help
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  • #2
The data you have given is definitely not a straight line graph.
between the 1st two values the difference is 6-5.3= 0.7
between the last two values it's 21-18 = 3
This will not give a straight line graph.
Is your data actually displacement against time? (Not velocity?)
The displacement against time graph will look like that.
In order to find the velocity of the cart, you need to do a calculation on the dots from the ticker tape. It's not read off directly.
If you have just read off directly from the tape, I'm certain that what you have measure is displacement, not velocity.
How did you find velocity?

1. What is a ticker tape?

A ticker tape is a long strip of paper with evenly spaced marks, used to measure the motion of an object. It was commonly used in scientific experiments before the invention of digital motion sensors.

2. How is the graph of a cart in motion using ticker tape created?

The graph is created by plotting the distance of the cart at regular intervals, using the marks on the ticker tape. The time intervals can also be plotted on the x-axis to show the speed of the cart.

3. What information can be gathered from the graph of a cart in motion using ticker tape?

The graph can provide information about the distance, speed, and acceleration of the cart. It can also show any changes in speed or direction during the motion.

4. How is the acceleration of the cart determined from the graph?

The acceleration can be determined by calculating the slope of the graph. A steeper slope indicates a greater acceleration, while a flatter slope indicates a slower acceleration.

5. What are the limitations of using a graph of a cart in motion using ticker tape?

One limitation is the accuracy of measurement, as the marks on the ticker tape may not be evenly spaced. Another limitation is that the graph can only show the motion of the cart in a straight line, and cannot account for changes in direction or motion in multiple directions.

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