Friction is a resistive force that opposes an object's motion or intended motion. The formula to compute the frictional force (f) is
f = µN
The coefficient ( µ) is unique for different materials. The normal force (N) is the countering force that the surface exerts on the object to oppose its weight.
We proceded as follows:
- Firmly attach the accelerometer to your wrist.
- Place an object on your wrist.
- Hit "Collect" in LoggerPro and gently raise your forearm up.
- Hit "Stop" when the object starts sliding.
- Determine and record the component of the acceleration due to gravity (a) parallel to your wrist at the instant that the object slips.
- Repeat steps 2–5 for four different materials.
After performing this experiment, we needed to compute the angle (θ) at which the object starts slipping. Since we know the acceleration components:
sin θ = a/g
After calculating the different critical angles, the coefficients µ can be calculated as follows:
N = mg cos θ
f = mg sin θ = µN = µmg cos θ
µ = tan θ
The data table below contains all our recordings and calculations.
|Material||Acceleration (m/s2)||Critical Angle (°)||Static Coefficient|
Harvey Lei, Genna Ableman, Bridget Ritter, Africa Belgrave -- 2005Students Choice
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