### PHY10L - E105

ANALYSIS (E105)

1.        Does the area of contact affect the coefficient of friction? Defend your answer.

The area of contact does not affect the coefficient of friction. Friction is equal to the product of the coefficient of friction and the normal force,    ƒ= μ n. Surface area does not directly affect the frictional force between two surfaces. If it did, it would be a factor in the equation for friction.

2.      Why is it necessary to observe uniform motion of the block in each procedure of experiment?

Observing uniform in motion is needed because, in general definition, where a body moves a constant speed or motion, kinetic friction is essentially constant. One can determine coefficient of friction between contact surfaces on one body which moves on uniform motion.

3.      How is the tan θ (angle of inclination) in Table 2 related to μ (coefficient of friction) in table 2? Why?

Since the summation of forces along y is equal to the summation of forces along x and is also equal to zero, solving for the normal force would be equal to the weight cos θ and friction would be equal to the weight sin θ. In general definition, ƒ = μ n, solving for μ would be equal to ƒ / n, substituting the values of friction and the normal force, by trigonometric identities and algebra, would just be equal to the tan θ.

CONCLUSION

1.        Are the objectives of the experiment met? Explain.

We were able to meet the objective of the experiment which is to determine the coefficient of friction (μ) between contact surfaces as one body moves with uniform motion and to establish the relationship between the angle of repose (θ) and μ.

Friction is the universal force between surfaces that opposes sliding motion. If there is relative sliding at the surface, the friction force always acts in the opposite direction of its motion. For dry surfaces the friction depends on the types of surfaces and on the normal force acting between them. In each procedure of the experiment, we consider the speed to be constant because one can determine coefficient of friction between contact surfaces on one body which moves on uniform motion. The tan of the angle of repose is equal to the coefficient of friction.

2.      Discuss the practical application of the concept/s learned from the experiment.

We can observe the presence of friction while walking or driving a car, the friction gives the required reaction so you can move forward or backward or while writing with a pen, pencil, or chalk, if there were no friction, the pen would just slip off. Everything you place remains where it is because friction prevents it from moving. If it weren't for friction, you would have to place the object on a perfectly flat surface and ensure it wasn't moving even slightly when you let it go to prevent the object from sliding off the surface. Frictional energy warms your hands when you rub them together on a cold winter day. Friction permits a car to hold a curve. Without the friction between the tires and the road surface, you would not be able to steer around a curve, because the car would want to travel in a straight line. What's more, without friction, the drive wheels would slip and spin and be unable to propel the vehicle.