Question Detail
Question
The coefficient of static friction between a box of mass 15 kg and horizontal surface is 0.2. If a force of 10.0 N is applied to the box, calculate the limiting frictional force between the two surfaces.
Correct Answer
Option B is the correct answer.
Detailed Explanation
Limiting frictional force (maximum static friction) is given by f_max = μ_s N, where N = mg = 15 × 10 = 150 N (using g=10). So f_max = 0.2 × 150 = 30 N. The applied force of 10 N is less than this, so the actual friction will be 10 N, but the limiting friction is the maximum possible, which is 30 N.
Hint
Limiting friction is the maximum static friction, given by μ_s times the normal force.