What is the average acceleration of a cart with photogates 30 cm apart?

• curiouspup34
In summary: Yeah that's true! Hm okay well I will assume constant acceleration now and go from there. Thank you for your help!
curiouspup34
Member advised to use the formatting template for all homework help requests
If the distance between the photogates in the diagram is 30 cm, and the times for the photogates on the LabQuest are listed as:
Blocked 0.00000
Unblocked 0.00156
Blocked 0.035
Calculate the average acceleration (in fundamental-standard units) of the cart. You should assume and initial velocity of 0 m/s and round your answer to 1 decimal place.

I know the average acceleration equation is delta v over delta t and I know how to find the change in velocity but I'm confused on what times to use.

My attempt:
Velocity=0.30m/(0.035)=8.5714m/s
Acceleration= (8.5714m/s-0m/s)/(0.035s-0s)=244.9m/s^2

curiouspup34 said:
Velocity=0.30m/(0.035)=8.5714m/s
Obviously, the velocity is not constant. Be specific about what velocity this is.

haruspex said:
Obviously, the velocity is not constant. Be specific about what velocity this is.
This would be the final velocity

curiouspup34 said:
This would be the final velocity
Not according to the way you calculated it.

haruspex said:
Not according to the way you calculated it.
Then the average velocity? If this is so, is my issue that I need to find the final velocity because they gave me the initial already?

curiouspup34 said:
Then the average velocity? If this is so, is my issue that I need to find the final velocity because they gave me the initial already?
Yes.
You will have to assume constant acceleration (which makes the request to find the average acceleration a bit misleading).

haruspex said:
Yes.
You will have to assume constant acceleration (which makes the request to find the average acceleration a bit misleading).
So I would have
v final = (0.30m/.035s)(2) = 17.143 m/s
Avg acceleration = (17.143m/s)/(0.035s)=489.8 m/s^2

curiouspup34 said:
So I would have
v final = (0.30m/.035s)(2) = 17.143 m/s
Avg acceleration = (17.143m/s)/(0.035s)=489.8 m/s^2
Yes, but as I wrote you have to assume constant acceleration in order to claim that final velocity, so it is misleading to call the answer an "average" acceleration. If the acceleration is not constant then the average acceleration will not have that value.

curiouspup34
haruspex said:
Yes, but as I wrote you have to assume constant acceleration in order to claim that final velocity, so it is misleading to call the answer an "average" acceleration. If the acceleration is not constant then the average acceleration will not have that value.
Yeah that's true! Hm okay well I will assume constant acceleration now and go from there. Thank you for your help!

1. What is a photogate and how does it work?

A photogate is a device used to measure the speed or velocity of an object. It works by emitting a beam of light that is interrupted when the object passes through it, which triggers a timer to start and stop. By measuring the time it takes for the object to pass through the photogate, the speed can be calculated.

2. How accurate are photogates in measuring speed?

Photogates are highly accurate in measuring speed, with a margin of error of only a few milliseconds. However, the accuracy can be affected by factors such as the distance between the photogate and the object, as well as the ambient lighting conditions.

3. Can photogates be used to measure acceleration?

Yes, photogates can be used to measure acceleration by measuring the change in speed over time. This can be done by setting up multiple photogates at different points along the object's path and using the data collected to calculate the acceleration.

4. What are some common applications of photogates?

Photogates have a wide range of applications in physics, engineering, and sports. They are commonly used in laboratory experiments to study motion and acceleration, in industrial settings to monitor production processes, and in sports to measure the speed and reaction time of athletes.

5. What are some potential sources of error when working with photogates?

Some potential sources of error when working with photogates include incorrect placement or alignment of the photogate, variations in the ambient lighting conditions, and human error in recording the data. It is important to carefully set up and calibrate the photogate system to minimize these sources of error.

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