A.Y. 2012-2013 – 3rd Quarter
Department of Physics
Experiment 105
FRICTION
Name: Alviar, Renée Hannah C.
Program/ Year: AR – I
Course Code/ Section: PHY10-2L – A2
Student No.: 2012170402
Group No.: 5
Date of Performance: February 18, 2013
Date of Submission: March 4, 2013
Instructor: Prof. Morris Martin M. Jaballas
GRADE:
DISCUSSION
During Part A (Determination of the Coefficient of Friction) of this experiment, as we determine Wb and Wp, we are then able to calculate for the coefficient of friction (µ) using the formula: µ = F/N = Wp (g)/ Wb (g)
In the first trial, we’ve used the wooden block alone and adjusted weights on top of the block and on the pans for the rest of the trials. It has been recorded under Wb and Wp respectively. As we’ve calculated for its coefficient of friction, we’ve accumulated the value 0.36 in the second trial as the highest among the 5 values. The coefficient of friction values range from 0.21 – 0.36 giving us an average µ of 0.29.
During Part B (Determination of the angle of repose) of this experiment, using summation of forces along the x- and y-axis can be equated to zero, hence the normal force is equal to Wcosθ and friction is equal to Wsinθ.
In every trial, the plane was being inclined such that the wooden block was observed in a uniform sliding motion. We recorded the data for vertical height (h) and horizontal distance (b) simultaneously in each trial. Given these data, we are able to calculate the tangent of the angle and the angle of repose using the equation: θ = tan-1(b/h)
These angles that we’ve calculated result constantly, with 7ᵒ as the lowest angle and 15ᵒ as the highest angle of repose.
In the last trial (Determination of Maximum Forces that cause Uniform Motion), we determined the experimental value of Wp that will cause the block to slide up at constant speed. The forces acting on the block are Wp, Wb, frictional force and normal force.
Wp =