# Physics Postlab Help - Get Answers to Questions

• Habibrobert
In summary: When the cart is accelerating, the string moves and the force sensor reads the tension in the string after the cart has moved.In summary, the student is questioning the accuracy of the prelab questions and feels that the problems are designed to trick the user. The student has determined that the acceleration is correct, but that the decimal point in the force on force sensor while accelrating is wrong. They are not sure if the negative value is meant to represent a push or a pull. The student has also found that the mass of the hanger is wrong.
Habibrobert
Hello everyone, I'm working on a physics postlab due tomorrow, and I'm just really skeptical that the answers I am getting so far are correct, I just feel like the problems are designed to "trick you" because of the values you are looking for are on the graph. could you guys please take a look at it and tell me how to do this particular page of the prelab correctly? The set up is a cart on a frictionless track that has a string tied to it which is also tied to some weight (the prelab calls it a hanger) that is hanging down and pulling on the cart. Attached a screen shot of the prelab

Thanks very much!

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• Screen Shot 2013-02-02 at 11.39.30 PM.png
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Check the decimal point for the force.
Where is that force measured?
How did you get the mass of the hanger?

The force is measured from the car, before and after it was released. I used F=m*a to find the mass of the hanger, but I feel like that is wrong.

Habibrobert said:
The force is measured from the car, before and after it was released.
In other words, it is the tension of the string connecting both?

I used F=m*a to find the mass of the hanger, but I feel like that is wrong.
It is hard to tell if you don't add which a and F you used. The mass looks wrong.

Is the force sensor mounted on the cart and the string tied to the force sensor?
• Accleration ok.
• Decimal point in force on force sensor while accelrating wrong. I am not sure if they want the negative though. All it means is that the force sensor is registering a pull , which is displayed as a negative value. A push on the sensor will be displayed as a positive value.
• Mass of the hanger wrong. The force sensor reads the (full) tension in the string when the cart is stationary.

## 1. What is the purpose of a physics postlab?

The purpose of a physics postlab is to reinforce and solidify the concepts and principles learned during a lab activity. It allows students to reflect on their experimental results and make connections to the theoretical concepts taught in class.

## 2. How can I get help with my postlab questions?

You can get help with your postlab questions by seeking assistance from your instructor, teaching assistants, or fellow classmates. You can also use online resources, such as forums or tutoring services, to get answers to your questions.

## 3. What should I include in my postlab report?

Your postlab report should include a summary of the lab activity, your experimental setup and methods, data collected during the experiment, and a discussion of your results. It should also include any calculations, graphs, or diagrams that support your findings.

## 4. How can I improve my postlab analysis and interpretation?

To improve your postlab analysis and interpretation, you should carefully review your lab notes and data, and make sure you understand the underlying principles and concepts. You can also seek feedback from your instructor or classmates and practice applying the theoretical concepts to real-world situations.

## 5. How can I use postlab discussions to enhance my understanding of physics?

Postlab discussions can enhance your understanding of physics by allowing you to engage in critical thinking and problem-solving. By discussing your results and findings with others, you can gain new perspectives and insights, and deepen your understanding of the concepts and principles involved in the lab activity.

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