Art a Calculate the Coefficient of Kinetic Friction Between the Box and Floor

Kinetic friction is a force that acts betwixt moving surfaces. An object that is beingness moved over a surface will feel a strength in the contrary direction as its move. The magnitude of the forcefulness depends on the coefficient of kinetic friction between the two kinds of material. Every combination is different. The coefficient of kinetic friction is assigned the Greek letter of the alphabet "mu" (μ), with a subscript "k". The force of kinetic friction is μ_k times the normal force on an object, and is expressed in units of Newtons (N).

forcefulness of kinetic friction = (coefficient of kinetic friction)(normal force)

F_thou = μ_k η

F_yard = force of kinetic friction

μ_k = coefficient of kinetic friction

η = normal force (Greek letter "eta")

Kinetic Friction Formula Questions:

one) A worker in a stock room pushes a large paper-thin box beyond the floor. The coefficient of kinetic friction is μ_{one thousand} = 0.520. The box has a mass of 75.0 kg, and the worker is exerting a force of 400.0 Nfrontwards. What is the magnitude of the force of friction, and what is the cyberspace force moving the box?

Respond: On a apartment surface, the normal forcefulness on an object is η = mg. Using this, the formula tin can be used to observe the force of friction:

F_k = μ_k η

F_k = μ_k mg

F_{one thousand} = (0.520)(75.0 kg)(9.80 m/due south² )

F_grand = 382.2 kg∙one thousand/south²

F_m = 382.2 N

The force of kinetic friction acting in the opposite management as the motility of the box is 382.2 N. The net forcefulness acting on the box is the sum of forces. The two forces to consider are the force of kinetic friction acting in the opposite direction every bit the box's motion, and the forcefulness exerted by the worker, which is 400 Northward frontwards. If we define "forward" as the positive direction, the net force is:

F_net=F_worker-F_k

F_net =400.0 N-382.iiN

F_cyberspace = 17.8 N

The cyberspace force acting on the box is 17.8 N forward.

two) A adult female is skiing straight downwardly a snow-covered hill. The coefficient of kinetic friction between the skis and the snowfall is μ₁₀₀₀ = 0.0800. The colina is at a 60.0° angle from the horizontal. The skier'south mass is 55.00 kg. What is the magnitude of the force of kinetic friction, and what is the net force along the skier's management of motion?

Respond: On a flat surface, the normal forcefulness on an object is η = mg. On a surface that is at an angle relative to the horizontal axis, The total force due to gravity, F = mg, must exist broken in to components. The normal force is the component that is perpendicular to the angled surface, and the remaining force is parallel to the angled surface. The normal force is η = mg cosθ, and the remaining force component is F = mg sinθ. Using this, the formula can be used to notice the magnitude of the force of kinetic friction:

F_k = μ_thousand η

F_grand = μ_k mg cosθ

F_yard = (0.0800)(55.00 kg)(9.lxxx m/s²)cos(60°)

F_g = 21.6 kg∙m/s²

F_k = 21.6 Due north

The strength of kinetic friction opposes the motion of the skier. The force that moves the skier down the loma is the remaining component of the strength of gravity, F_θ = mg sinθ. This force is:

F = mg sinθ

F =(55.0 kg)(ix.80 m/south^two )sin(threescore°)

F = 466.8kg∙g/s²

F = 466.8N

The cyberspace strength acting on the skier is the sum of forces. The 2 forces to consider are the force directed down the loma and the force of kinetic friction directed up the hill. If nosotros define the positive direction every bit down the hill, which is the skier's direction of motion, the net forcefulness is:

F_net = F-F_k

F_net = 466.8 N-21.half dozen N

F_cyberspace = 445.two N

The internet strength acting on the skier in her direction of move is on the box is 445.ii Northward.

sandersalver1938.blogspot.com

Source: https://www.softschools.com/formulas/physics/kinetic_friction_formula/92/

Bagikan Artikel ini