A box is lying still on an inclined plane. The inclination angle (from the horizontal) of the plane is . At a certain moment, the box is being punched. This punch sets the box in motion up the inclined plane. The box climbs until it comes to a stop. The scenario is depicted in the clip. The coefficient of kinetic friction between the box and the plane is
What is the lower limit that can be placed on the value of the static friction coefficient, ?
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True. If the box can lie still, it must be that the the static friction force, , and the component of the weight balance, so . In addition, . The normal force balace the prependicular component of the weight, therefore . combining these three relation we get
Not true. The box will come to a stop and then remain at rest due to static friction force.
Wrong. It might be that the static friction coeffcient is larger that 0.5 but a stronger lower limit can be placed.
Wrong for many reasons. 1. This is not a lower limit. 2. This is not true. it is possible to have