LabPro InterfaceMotion detectorForce sensorForce software fileDynamics trackDynamics cartPulleyHanging masses

Introduction

The pressure sensor is a device that steps the amount of force applied to the hook attached to the sensor. The sensor deserve to only measure the force component used parallel come its length, and also forces directed far from the sensor are typically regarded as positive.

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The pressure sensor measures force by means of a strain gauge. Together a force is applied to the sensor, a small metal bar within the sensor deforms. Strain gauges attached to the bar readjust resistance as the bar deforms. This change in resistance outcomes in a adjust in voltage. In stimulate to transform this voltage info into pressure information, the sensor should be calibrated.

The sensor is calibrated by means of a two-point calibration. First, no force is used to the sensor and also the result voltage is recorded. Climate a known pressure is applied and the result voltage recorded. Utilizing these 2 points together reference, and assuming a linear relationship in between force and also voltage, any voltage reading have the right to be converted right into a pressure reading. Since the force sensor is accurate enough to recognize the load of the hook, that should constantly be calibrated in the same orientation in i m sorry it will certainly be used.

In this activity, you will certainly measure both the motion of a cart making use of the activity detector and the force applied to the cart making use of the force probe. The relationship between the pressure acting on an item and that is subsequent motion is of central importance in many branches of physics.

I. Calibrating the force Sensor

Open the paper Force.

Set the sensor to the ±10 N setting and securely affix it come the optimal of the cart. Ar the cart at remainder on the track.

To calibrate the pressure sensor, pick Experiment/Calibrate and choose the pressure sensor. Select Calibrate Now. Friend will perform a two-point calibration the the sensor:

For the first calibration point, execute not apply any type of force to the sensor, enter 0 N, and also hit Keep. For the 2nd calibration point, affix a 200 g mass come the sensor by method of a cable passing end the pulley. Go into the force of gravity acting on this fixed (1.96 N) and also hit Keep.

The sensor is now calibrated.

To inspect the calibration the the sensor, complete the adhering to table. In every case, connect the proper hanging mass, organize the dare at rest, and collect pressure data for number of seconds. Uncover the mean and standard deviation the the force sensor data.

Hanging mass (g)

Weight (N)

Mean Sensor reading (N)

0

±

50

±

100

±

150

±

200

±

500

±

You are currently going to produce a graph, with error bars, of load vs. Average Sensor Reading. To do this in LoggerPro:

Select Insert/Table to check out your data table. Uncover the empty columns labeled y-axis, delta y, x-axis, delta x. (The various other columns room filled through the last collection of data friend collected. You can delete or just ignore this data.)Enter your data right into the ideal column. (Weight ~ above the y-axis, sensor analysis on the x-axis, and the hesitation in sensor analysis as delta x.)Double-click top top each tower header to readjust the label and also units because that each column.Create a graph of weight vs. Typical Sensor analysis by an altering the variables on the x- and y-axis of one of your pre-existing graphs.Right-click on the graph, select Graph Options/Graph Options, and also deselect the option Connect Points.Based on her data, choose an ideal best-fit role (Analyze/Linear Fit or Curve Fit) and also display it on your graph. Remember, a best-fit role should it is in the simplest possible function that accurately matches your data.

Finish preparing her graph, then print and also attach it to the finish of this activity.

Question: record each constant in your best-fit function below. Each numerical value must have actually both uncertainties and units. (To recognize the unpredictabilities in direct fit parameters, right-click in the straight Fit box and select Linear to the right Options. This screens the conventional deviation the the slope and also y-intercept.)

Question: If the pressure sensor accurately steps the force applied to it, what must the slope and also y-intercept of your best-fit duty equal? Explain.

Question: does your force sensor accurately measure up the force applied to it? Explain.

II. Force and also Initial Motion

Display graphs that force and also acceleration vs. Time.

Attach 200 g come the sensor via a string passing over the pulley. Host the cart in place about 20 centimeter in front of the activity detector, push Collect, and also after about 1 second of data collection release the cart. Make certain that the track is clean, the wheels of the cart revolve freely, and also the force sensor cord does not drag behind the cart.

Once you have recorded a clean run of the experiment, correctly prepare and print your graph and attach it to the finish of this activity. Attract a vertical heat (through both graphs) at the moment you released the cart. Brand the line “Release”.

Question: Your pressure vs. Time graph should present a clear decrease in force when you exit the cart. Is this diminish in pressure real (meaning the force used to the cart actually does decrease once the dare is released) or is it a glitch (due come an imperfect measuring device)? If it is real, define why the force suddenly decreases. If the is a glitch, hypothesize what is wrong through the measure device.

Question: If the hanging mass was much less massive, would the discontinuity in force be bigger or smaller in magnitude? Explain.

Test your prediction by making use of a smaller sized magnitude hanging mass. Do not continue until you understand the nature of the discontinuity in the pressure vs. Time graph.

III. Force and also Acceleration

Using the hanging masses provided below, release the cart from rest and also measure the mean pressure acting top top the dare (after release) and the mean acceleration the the cart. Make sure that her data is clean and also accurate before assessing it, and only analyze the appropriate section of the data. You should analyze the same time interval on both graphs.

Print out and attach among your trials v the region analyzed highlighted and also the relevant statistics displayed. Show this graph to your instructor to verify the you are assessing the data correctly!

If at any time you think your pressure sensor is developing erroneous readings, simply check the calibration by hanging a well-known weight native the sensor. Occasionally the sensor deserve to “drift”. This deserve to be corrected by re-zeroing the sensor making use of the Zero switch on the toolbar. If the readings are dramatically off, you might need come re-calibrate your sensor.

Hanging mass

(g)

Mean Force

(N)

Mean Acceleration

()

200

±

±

150

±

±

100

±

±

50

±

±

Create a graph, through error bars because that both the y- and also x-data, that Mean pressure vs. Average Acceleration. (Insert/Table to see your data table and also simply “type-over” her previous inputted data. Psychic to adjust the labels and also units because that each column.)

Based on your data, select an appropriate best-fit role (Analyze/Linear Fit or Curve Fit) and also display the on her graph. Remember, a best-fit function should it is in the simplest feasible function the accurately matches her data.

Finish preparing her graph, climate print and attach it to the end of this activity.

Question: record each continuous in your best-fit duty below. Every numerical worth must have both uncertainties and units. (To determine the uncertainties in straight fit parameters, right-click in the linear Fit box and also select Linear fit Options. This screens the conventional deviation the the slope and y-intercept.)

Applying Newton’s 2nd Law to the dare in the direction of motion results in:

Rearranging this equation outcomes in:

Question: your graph involved the force of the cable on the y-axis and the acceleration the the dare on the x-axis. Based on this observation, and a straightforward comparison in between your best-fit duty and Newton’s 2nd Law, what is the combined mass of your cart and also sensor (with units and uncertainties) and also what is the average frictional force acting on her cart (with units and uncertainties)? just how did you determine these values?

Question: making use of a scale, recognize the linked mass of her cart and also sensor and also record the below. Compare this worth to the value figured out above. Discuss the accuracy the your experimental data.

IV. Mass and also Acceleration

In the vault activity, the force used to the cart was varied and the mass of the cart was hosted constant. In general, that a an excellent idea to differ as couple of parameters as possible when conducting an experiment. In this experiment, girlfriend will host the force constant while you differ the mass.

This is contempt more daunting since, together you saw previously in this activity, the force used to the cart is no equal come the weight of the hanging mass. Therefore, even if the hanging massive is hosted constant, the force it exerts ~ above the cart will not be constant.

For example, if we think about the cart together the device of attention (as we did in the vault activity), the force sensor steps the force applied to the cart, however this pressure is no equal to the weight of the hanging mass.

Ffriction

Ffriction

Fstring ≠ 1.96 N

Fstring ≠ 1.96 N

However, if we consider the cart and hanging mass with each other as the system of interest, the force used to the mechanism is equal to the weight of the hanging mass, i m sorry is straightforward to save constant. Notice, for this system, the the pressure sensor doesn’t measure anything useful! The two forces acting ~ above the mechanism are the load of the hanging mass and the friction on the cart. This is the mechanism we will certainly experiment through below.

Ffriction

Ffriction

Fgravity = 1.96 N

Fgravity = 1.96 N

Using a 200 g hanging mass, collection data to complete the table below. Begin with a mechanism of cart, sensor and 200 g hanging mass. Then, continually include 500 g to the system to complete the experiment. Make certain that her data is clean and also accurate before evaluating it, and also only analyze the appropriate portion of the data.

System

System fixed

(kg)

Mean Acceleration

()

cart, sensor, 200 g

±

+500 g

±

+500 g

±

+500 g

±

+500 g

±

Create a graph of system Mass vs. Median Acceleration. Incorporate the suspicion in the median acceleration.

Based on your data, pick an proper best-fit role (Analyze/Linear Fit or Curve Fit) and display it on her graph. Remember, a best-fit role should be the simplest possible function that accurately matches her data. Additionally, due to the fact that you recognize this motion is governed by Newton’s 2nd Law, her best-fit duty should agree with Newton’s legislation in practical form.

Question: beginning from Newton’s 2nd Law applied in the direction of motion of the system, rearrange Newton’s law until fixed is diverted on the left-side of the equation. (Your best-fit role should have this form.)

Print your graph through best-fit function displayed and also attach it come the finish of this activity.

Question: record each consistent in her best-fit duty below, with units and uncertainties.

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Question: based on your best-fit function, what is the net force (with units and uncertainty) that acts on the system?

Question: based on your best-fit function, and also the monitoring that you supplied a 200 g hanging massive to advice the system, what is the mean frictional pressure (with units and uncertainty) that acts on the system? Is this worth the exact same as in the ahead experiment? have to it be? very closely explain.