Friction Basics
A 2 kg block is pushed against a vertical wall by applying a horizontal force of 50 N. The coefficient of static friction between the block and the wall is 0.5. A force F is also applied on the block vertically upward (as shown in figure). The maximum value of F applied, so that the block does not move upward, will be:
(Given: g = 10 ms2)

Show answer and solution
Answer: (d)
- Normal force N, so limiting friction N.
- When the block is about to move up, friction acts downward along with the weight.
- N, so the answer is (d).