The total force needed to drag a box at constant speed across a surface with coefficient of kinetic friction μ_k is least when the force is applied at an angle θ such that A) sinθ = μ_k. B) cosθ = μ_k. C) tanθ = μ_k. D) cotθ = μ_k. E) secθ = μ_k.

Question

Quizplus · Accepted Answer

The minimum force needed to drag a box at constant speed is when the force is applied at an angle θ such that the component of force parallel to the surface is equal and opposite to the force of friction. This can be represented by the equation Fcosθ = μkFn, where F is the total force, θ is the angle between the force and the surface, μk is the coefficient of kinetic friction, and Fn is the normal force. Solving for cosθ, we get cosθ = μk. Therefore, the best choice is C, tanθ = μk.

The Total Force Needed to Drag a Box at Constant