Answer:
a) 35 kPa
d) 140 N
c) 1) Increasing the brake fluid pressure
2) Increasing the slave piston surface area.
Explanation:
The parameters given are;
a) Force applied to the master cylinder piston = 28 N
Cross sectional area of the master cylinder piston = 8 cm² = 8 × 10⁻⁴ m²
The pressure P on the brake fluid is given by the formula for pressure as follows;

The pressure on the brake fluid, P, produced by the master cylinder piston = 35,000 Pa = 35 kPa
b) Given that the area of the slave piston = 40 cm² = 0.004 m², we have from the formula for pressure, P;

Therefore;
Applied force on the slave piston = 4 × 10⁻³ m² × 35,000 N/m² = 140 N
c) The force, F produced by the slave cylinder piston is given by the relation;
F = Pressure × Area
Therefore, the two ways of increasing the force produced by the slave cylinder piston is as follows;
1) Increasing the pressure in the brake fluid by increasing the force exerted by the master cylinder piston
2) Increasing the surface area of the slave piston.