# How Does Gravity Affect Kinetic Energy in a Glider System?

• aron silvester
Thanks for clarifying!In summary, the student discusses a physics lab experiment involving a glider and a string attached to a pulley. Work is done by gravity, resulting in a gain of kinetic energy for the system. The student uses a motion sensor to collect data and is asked to calculate the change in kinetic energy relative to the initial kinetic energy at each time the velocity was taken. There is confusion about the initial and final velocity values and the accuracy of measurements. The link to the lab setup and data is provided for further reference.
aron silvester

## Homework Statement

This is a lab I did for physics. In this experiment, a glider starting from rest on an air track is attached to a string. The string is drawn over a pulley with a mass hanger tied to the other end. Work is done by gravity which results in a gain of kinetic energy of the entire system. There is a motion sensor located at the left end of the air track, which is where I got the data on the left side of the picture. I placed my hand on the glider, turn on the fan, wait for 3.4 seconds before letting go of the glider and the glider moves to the right. The glider hits the end of the air track and that's the end of data collection. There is a question in the picture which is question #14.

#14.) The total system (glider + hanger + masses) is moving with a velocity given by the velocity data you exported. Calculate the change in kinetic energy of the system relative to the initial kinetic energy (zero kinetic energy relative to the motion sensor when starting from rest) at each time the velocity was taken. This should be done in excel to be used for a graph requested later.

Below this question in the picture is my attempt.

My question: What will be my new and final data points after the calculations that I showed? Of course, I will not be doing this by hand, I will be doing it on excel, but I’m just showing the calculations for the purpose of showing how I am thinking. In the question, it says, “Calculate the change in kinetic energy of the system relative to the initial kinetic energy (zero kinetic energy relative to the motion sensor when starting from rest) AT EACH TIME THE VELOCITY WAS TAKEN”.

My first set of calculation had initial velocity = 0.07m/s and final velocity = 0.03m/s. Does that mean that my next calculation will use initial velocity = 0.03m/s and final velocity = 0.12m/s?

I’m really confused. Below is a link to all the information, data collected and illustration of the lab setup that you need to know. If you need any more information, please ask. Thanks!

Use this link, it's clearer. Just zoom into see better.
https://myhpu-my.sharepoint.com/per...cedc60b090147&authkey=ASjBnzRP8Gxa2cRQW2GTupo

## Homework Equations

It's all in part 1

## The Attempt at a Solution

It's all in part 1

#### Attachments

• PHYSICS LAB 7 .png
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aron silvester said:
My first set of calculation had initial velocity = 0.07m/s and final velocity = 0.03m/s.
That clearly makes no sense. There is a risk that the initial movement is confused by the way you let go of the glider. It might jitter a little. I would start at the last value that shows a position of .47.

aron silvester said:
Does that mean that my next calculation will use initial velocity = 0.03m/s and final velocity = 0.12m/s?
I think it means constructing a column with entries ΔKi = Ki - 0, in other words the instantaneous kinetic energy assuming that you start at zero. That is how I interpret the statement between parentheses in “Calculate the change in kinetic energy of the system relative to the initial kinetic energy (zero kinetic energy relative to the motion sensor when starting from rest) AT EACH TIME THE VELOCITY WAS TAKEN”. I don't think you are asked to find changes in kinetic energy between adjacent velocity readings, i.e. ΔKi = Ki+1 - Ki. However, I agree with @haruspex that the first two readings need explaining. What is the accuracy of your measurements?

Douglas Sunday
kuruman said:
I think it means constructing a column with entries ΔKi = Ki - 0, in other words the instantaneous kinetic energy assuming that you start at zero. That is how I interpret the statement between parentheses in “Calculate the change in kinetic energy of the system relative to the initial kinetic energy (zero kinetic energy relative to the motion sensor when starting from rest) AT EACH TIME THE VELOCITY WAS TAKEN”. I don't think you are asked to find changes in kinetic energy between adjacent velocity readings, i.e. ΔKi = Ki+1 - Ki. However, I agree with @haruspex that the first two readings need explaining. What is the accuracy of your measurements?

haruspex said:
That clearly makes no sense. There is a risk that the initial movement is confused by the way you let go of the glider. It might jitter a little. I would start at the last value that shows a position of .47.
Alright, I'll try that.

## What is work?

Work is defined as the transfer of energy from one object to another by applying a force over a distance. In simpler terms, it is the force applied to move an object a certain distance.

## How is work calculated?

Work is calculated by multiplying the force applied to an object by the distance it is moved in the direction of the force. This can be represented by the equation W = F x d, where W = work, F = force, and d = distance.

## What is kinetic energy?

Kinetic energy is the energy an object possesses due to its motion. It is dependent on the mass and velocity of the object, and can be calculated by the equation KE = 1/2 x m x v^2, where KE = kinetic energy, m = mass, and v = velocity.

## What is the relationship between work and kinetic energy?

Work and kinetic energy are closely related, as work is the transfer of energy and kinetic energy is the energy an object has due to its motion. The work done on an object is equal to its change in kinetic energy, or W = ΔKE.

## How is the principle of conservation of energy related to work and kinetic energy?

The principle of conservation of energy states that energy cannot be created or destroyed, only transferred or transformed. In the context of work and kinetic energy, this means that the work done on an object will result in an equal change in its kinetic energy. In other words, the total amount of energy in a closed system will remain constant.

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