Concepts Of Physics MCQ Edition [Volume 1]PhysicsFriction
A body of mass M is placed on a rough horizontal surface having a friction coefficient . A person attempts to pull the body by applying a horizontal force, yet the body remains stationary. If the force exerted by the surface on the body is F , then
Options
- AF = Mg
- BMg F Mg 1 - ^2
- CF = Mg
- DMg F Mg 1 + ^2
Correct answer
D. Mg F Mg 1 + ^2
Step-by-step solution
The force exerted by the surface on the body is the resultant contact force, which is the vector sum of the normal reaction N and the force of static friction f . F = N^2 + f^2 Since the body is in vertical equilibrium on a horizontal surface, the normal reaction is equal to the weight of the body. N = Mg The body remains stationary under the applied horizontal force, so the static friction f is self-adjusting. Its value ranges from zero to the limiting friction. 0 f N 0 f Mg Substituting the minimum and maximum va