Conduct the experiment

1.

Place the flat object on a flat horizontal surface like the floor or a table. Let us say

that you are using a large book with a hardcover as a flat object.

2.

On the book, place both the phone and one of the three small objects you will be

using to determine the coefficient of static friction. Please check our video

explanation.

3.

On the Phyphox App select "Inclination".

4.

Maintain the first option " Flat tab" and start running the data collection. You will

read the values on the "Tilt up/down" plot.

5.

Very slowly raise one end of the book up until the object just starts to slide down

the incline. At the same time, hold the phone on the surface with your hand.

6.

The phone screen will display the increasing angle of inclination.

7.

Stop the data collection and tap on the screen.

8.

From the bottom of the screen select "Pan and Zoom" and then "Pick Data".

9.

Pick the angle that is the largest value during the inclination interval.

10.For each trial, take a screenshot of your smartphone with the point selected and

include it at the end of the report. You should have a total of 9 screenshots at the

end of your report.

11. Report this angle on the table below

in the "Results" section and calculate the

value of

using the Eq. 1.

12.Repeat the same steps for two more trials and report the values of the angles

and of the coefficients of static friction on the tables in the "Results" section.

13.Find the average of the three coefficients of friction

for that object.

14.Repeat the same experiment for the other two objects.

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15.Complete the tables below with your data. Be mindful of significant digits when

you report your data.

Alternative angle measurement method for students who do not have the smartphone.

Instead of collecting the angle value with the App Phyphox, you may measure it using a

ruler and two sets of data. First, measure the vertical height at which you raised the end

of the large book. Second, measure the length of the book itsself. Determine the

maximum angle of inclination using this trigonometric formula in your calculator.

heig ht measured

1

Angle

=

sin

(

)

lengt hmeasured

Results (9pts total points)

a. (0.5pt) Object 1: Which material did you use? [

Answer]

b. (0.5pt) Object 1: Average coefficient of friction, = [

Answer]

Data for Object 1 (2pts)

Angle of inclination (in degree)

Coefficient of statics friction

[Show your

work]

a. (0.5pt) Object 2: Which material did you use?

b. (0.5pt) Object 2: Average coefficient of friction, =

Data for Object 2 (2pts)

Angle of inclination (in degree)

Coefficient of statics friction

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