Question

The principle of fluid pressure that is used in hydraulic brakes or lifts is that
A. pressure is the same at all levels in a fluid.
B. increases of pressure are transmitted equally to all parts of a fluid.
C. the pressure at a point in a fluid is due to the weight of the fluid above it
D. increases of pressure can only be transmitted through fluids.

Answer 1

Hint: In this question, we need to comment on the principle of fluid pressure which is used in hydraulic brakes. For this, we will go through Pascal's law of fluid and try to relate the things with the given statement.

Complete step by step answer:
The first statement is itself wrong as pressure is not the same at all levels. The pressure increases with increase in depth from the surface of the Earth. In fact pressure is directly proportional to depth.
The statement that the pressure at a point in a fluid is due to the weight of the fluid above it is true but it is not the working principle for hydraulic brakes and lifts.
Hydraulic lifts and brake in fact works on Pascal’s Law. Pascal’s law states that when pressure is applied to any point in an enclosed fluid, the same magnitude of pressure will be transmitted to every other point of the fluid and to the walls of the container.

So, the correct answer is “Option B”.

Note:
Hydraulic lifts use fluids for lifting objects. There is no need for physical lifting. One needs to push one arm and the object in the other arm gets lifted. Fluids are also used in a similar mechanism in hydraulic brakes. Using Pascal’s law, we can even increase the force that we can apply by making changes in the area of contact. Hydraulics is an efficient way to lift heavy objects. It is assured that the fluid used in it is an incompressible fluid.