Tag: hydraulic equipment

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Multiple choice physics pressure in fluids and atmospheric pressure hydraulic equipment applications of pascals law examples of hydraulic press

State the principle on which a hydraulic press works. 

  1. Archimedes principle

  2. Bernoulli's principle

  3. Pascals Law

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

It works on the principle of Pascals law.
Pascal's law: Pressure on a confined fluid is transmitted undiminished and acts with equal force on equal areas and at 90 degrees to the container wall.
Uses of hydraulic press - Hydraulic presses are commonly used for forging, clinching, moulding, blanking, punching, deep drawing, and metal forming operations.

Multiple choice physics pressure in fluids and atmospheric pressure hydraulic equipment applications of pascals law examples of hydraulic press

The principle of fluid pressure that is used in hydraulic brakes or lifts is that.

  1. pressure is the same at all levels in a fluid.

  2. increases of pressure are transmitted equally to all parts of a fluid.

  3. the pressure at a point in a fluid is due to the weight of the fluid above it.

  4. increases of pressure can only be transmitted through fluids.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Answer is B.
Hydraulics is the use of a liquid under pressure to transfer force or motion, or to increase an applied force. The pressure on a liquid is called HYDRAULIC PRESSURE. And the brakes which are operated by means of hydraulic pressure are called HYDRAULIC BRAKES. These brakes are based on the principle of Pascals law. 
The Pascal law states that 'The pressure exerted anywhere in a mass of confined liquid is transmitted undiminished in all directions throughout the liquid'.

Multiple choice physics pressure in fluids and atmospheric pressure hydraulic equipment applications of pascals law examples of hydraulic press

In a hydraulic lift, used at a service station the radius of the large and small piston are in the ratio of 20 : 1. What weight placed on the small piston will be sufficient to lift a car of mass 1500 kg ? 

  1. 3.75 kg

  2. 37.5 kg

  3. 7.5 kg

  4. 75 kg
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The answer is A.

Pressure is the amount of force acting per unit area. That is, P=F/A.
where:
p is the pressure,
F is the normal force,
A is the area of the surface on contact. Let us consider A = $\pi { r }^{ 2 }$.
Therefore, $\dfrac { { F } _{ 1 } }{ { \pi { r } _{ 1 } }^{ 2 } } =\dfrac { { F } _{ 2 } }{ { \pi { r } _{ 2 } }^{ 2 } } $.


In this case, $\dfrac { 1500 }{ { 20 }^{ 2 } } =\dfrac { W }{ { 1 }^{ 2 } } ,\quad W\quad =\quad 3.75\quad kg.$
Hence, weight to be placed on the small piston sufficient to lift a car of mass 1500 kg is 3.75 kg.

Multiple choice physics pressure in fluids and atmospheric pressure hydraulic equipment applications of pascals law examples of hydraulic press

Hydraulic press is based upon :-

  1. Archimede's principle

  2. Bernoulli's theorem

  3. Pascal's law

  4. Reynold's number
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Hydraulic press works on Pascal's principle, which states - “pressure throughout a closed system is constant.” 


In hydraulic press, there is a piston at one end of the system having a small cross-sectional area. This piston is driven by a lever. The other end of the system has small-diameter tubing. 
When a fluid is displaced, either of the pistons is pushed inward. Small piston displaces a smaller amount of volume than the large piston for a given distance of movement. The displaced fluid volume is proportional to the ratio of pistons' head areas. Hence, smaller piston moves a large distance to move large piston significantly. The large piston movement distance is equal to small piston movement distance divided by the ratio of the pistons' head areas.

Multiple choice physics pressure in fluids and atmospheric pressure hydraulic equipment applications of pascals law examples of hydraulic press

A mechanical machine which is used to lift or compress large loads.

  1. hydraulic press

  2. hydraulic lifts

  3. hydraulic brakes

  4. none
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A hydraulic press is a mechanical machine used to lift or compress large loads. A hydraulic press consist of two cylinders $C _1$ and $C _2$, fitted with pistons, valves and tubes.

Multiple choice physics pressure in fluids and atmospheric pressure hydraulic equipment applications of pascals law examples of hydraulic press

................ works on the Pascal's law and is used in automobiles.

  1. Hydraulic press

  2. Hydraulic lift

  3. Hydraulic jack

  4. All
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Hydraulic brake confirms to Pascal's law and is used in automobiles. It consist of a master cylinder filled with brake oil and provided with an airtight frictionless piston.

Multiple choice physics pressure in fluids and atmospheric pressure hydraulic equipment applications of pascals law examples of hydraulic press

The pump tube of hydraulic press is of cross section area $a$ and is connected with a press tube of cross section area $A$ such that :

  1. $a>A$
  2. $A>a$
  3. $A=a$

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In the construction of hydraulic press, release valve and press foot valves are there.

Hydraulic press consist of a pump tube of cross sectional area $a$ connected with a press tube of cross sectional area $A$ such that $A>a$.
The lower end of the pump tube is connected with a smaller tube which is further connected with an underground water tank.
At the junction of the pump tube and the smaller tube is fitted $a$ "pump foot valve" which opens in the upward direction only.

Multiple choice physics pressure in fluids and atmospheric pressure hydraulic equipment applications of pascals law examples of hydraulic press

Discharge of centrifugal pump is

  1. inversely proportional to diameter of its impeller
  2. inversely proportional to $diameter^2$ of its impeller

  3. directly proportional to (diameter)2 of its impeller

  4. directly proportional to diameter of its impeller
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Discharge of centrifugal pump is inversely proportional to square of the diameter of its impeller, thus option B is correct.