Answer:
49 N 
Explanation:
We are given;
- Mass of the brick as 3 kg 
- The coefficient of friction as 0.6 
We are required to determine the force that must be applied by the woman so the brick does not fall.
- We need to importantly note that;
- For the brick not to fall the, the force due to gravity is equal to the friction force acting on the brick.
- That is; Friction force = Mg 
But; Friction force = μ F
Therefore;
 μ F = mg 
0.6 F = 3 × 9.8 
 0.6 F = 29.4 
       F = 49 N 
Therefore, she must use a force of 49 N