Sainik School Entrance Exam 2018 Solved Paper

(a) When the force is doubled and the object is still at rest, then the friction is static friction. The maximum force of static friction is directly proportional to the applied force and is independent of the area of contact. When an object moves due to application of force the friction is said to kinetic friction which is less than static friction. Hence when we double the application of force the static friction also gets doubled.