brake-shoe-physics-ฟิสิกส์มัธยมปลาย-ฟิสิกส์ ม.5

Main Menu

Problem h2b1: Brake system;Disc brake

Problem h2b2: Brake system;Drum brake

Consider the automobile hydraulic system shown in Figure a
A force of 100 N is applied to the brake pedal, which acts on the cylinder-called
the master-through a lever. The master cylinder has a diameter
0.500 cm. The slave cylinder (Drum brake) has a diameter 2.50 cm.
Calculate the force at each of the slave cylinders.

Strategy

Force is increased by the simple lever, and again by the hydraulic system.

Pascal's law - pressure applied anywhere to a body of fluid causes a force to be transmitted equally in all directions; the force acts at right angles to any surface in contact with the fluid; "the hydraulic press is an application of Pascal's law"

Solution

1. We take "O" to be fulcrum to find F₁

Then 500 N. is exerted on the master cylinder.
Pressure created in the master cylinder is transmitted to four so-called slave cylinders.
Then we calculate the Force at the slave cylinders each.
The circle cross sectional area of master and slave cylinder are A₁  A₂  respectively.
Hence we can find the force  F₂  at the brake drum.

Ans.   The force at each of the slave cylinders is 1.25 x 10⁴ N.

Brake Shoe