Scelta multipla
In the context of kinetic friction in machinery, how do ball bearings primarily reduce friction compared with two surfaces sliding directly against each other?
63
views
7. Friction, Inclines, Systems
Kinetic Friction
Scelta multipla
In the context of kinetic friction between two solid surfaces, which method will most directly reduce the kinetic frictional force for a given normal force ?
A
Apply a lubricant between the surfaces to reduce the coefficient of kinetic friction .
B
Increase the normal force by pressing the surfaces together more strongly.
C
Increase the contact area while keeping the materials and normal force the same.
D
Increase the roughness of both surfaces to increase mechanical interlocking.
Guida verificata passo dopo passo1
Recall the formula for kinetic frictional force: \(f_{k} = \mu_{k} N\), where \(f_{k}\) is the kinetic frictional force, \(\mu_{k}\) is the coefficient of kinetic friction, and \(N\) is the normal force.
Understand that for a given normal force \(N\), the kinetic frictional force \(f_{k}\) depends directly on the coefficient of kinetic friction \(\mu_{k}\).
Analyze how each method affects \(\mu_{k}\) or \(N\): applying a lubricant reduces \(\mu_{k}\), increasing normal force \(N\) increases \(f_{k}\), increasing contact area does not affect \(f_{k}\) significantly in kinetic friction, and increasing roughness tends to increase \(\mu_{k}\).
Conclude that the most direct way to reduce \(f_{k}\) for a fixed \(N\) is to reduce \(\mu_{k}\) by applying a lubricant between the surfaces.
Therefore, applying a lubricant lowers the coefficient of kinetic friction, which directly reduces the kinetic frictional force without changing the normal force.
Video correlati
Pratica correlata
