Tag: physics

Questions Related to physics

Principle of similitude forms the basis for:

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

  1. comparing two identical equipments

  2. designing models so that the result can be converted to prototypes

  3. hydraulic designs

  4. performing acceptance tests

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Correct Option: B
Explanation:

The principle of similitude is a supplement to the scientific method advocated by Lord Rayleigh that requires that any suggested scientific law be examined for its relationship to similar law.

This principle forms the basis for designing models so that the result can be converted to prototypes.
Hence, option B is correct.

State True or False.
Hydraulic press is used in the extraction of oil from oil seeds.

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

  1. True

  2. False

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Correct Option: A
Explanation:

Hydraulic press is used in extraction of oil from oil seeds by crushing.

The concept of the hydraulic press is based on Pascal's theory, which states that when pressure is applied on fluids in an enclosed system, the pressure throughout the system always remains constant. In simple words, a hydraulic press is a machine that makes use of the pressure exerted on the fluids to crush something.

A hydraulic press contains 0.25 $m^3$ (250 L) of oil. Find the decrease in volume of the oil when it is subjected to a pressure increase $\Delta p \, = \, 1.6 \, \times \, 10^7$ ,Pa. The bulk modulus of the oil is $B \, = \, 5.0 \, \times \,10^9$ Pa.

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

  1. $-0.32 \%$ 

  2. $-1.32 \%$ 

  3. $-0.42 \%$ 

  4. $-1.42 \%$ 

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Correct Option: A

In a single movable pulley, if the effort moves by a distance $x$ upwards, by what height is the load raised?

physics machines levers and pulleys pulley pulleys

  1. $x/2$

  2. $x$

  3. $4x$

  4. $2x$

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Correct Option: A
Explanation:
Load $L$ is attached to the movable pulley. A rope is fi xed at a point in ceiling that passes through the moveable pulley. 
In order to lift the effort $E$ by $ x$ meters, the load $L$ needs to 
Travel the distance of $ x/2$ meters. (The entire rope needs to be pulled by $E$ for a distance of $ x$) 
Now, Velocity Ratio equals (Distance traveled by $E$) divided by (Distance traveled by $L$) 
So it becomes : $ x/( x/2)$. This equals to 2
Since it is a ratio. it has no units of measurement. 

What is the velocity ratio of a single movable pulley?

physics machines levers and pulleys pulley pulleys

  1. $1$

  2. $0.5$

  3. $2$

  4. $1.5$

Show answer
Correct Option: C
Explanation:

Load $L$ is attached to the movable pulley. A rope is fixed at a point in ceiling that passes through the movable pulley.
In order to lift the load $L$ by $X$ meters, the effort $E$ needs to travel the distance of 2X meters. (The entire rope needs to be pulled by $E$ for a distance of 2X.)
Now, Velocity Ratio equals (Distance traveled by $E$) divided by (Distance traveled by $L$)
So it becomes : $2X/X$. This equals to 2
Since it is a ratio. it has no units of measurement.

Example of wheel and axle is :

physics common machines levers and pulleys pulley pulleys

  1. Egg-beaters

  2. Egg-whiskers

  3. Clocks

  4. Electric saw

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Correct Option: B

Which of these is not an example of a fixed pulley?

physics machines levers and pulleys pulley pulleys

  1. well

  2. Flagoogle

  3. Crane

  4. None of these

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Correct Option: A
Explanation:

Both crane and flagpole comprises of pulley but not well. 

A simple pulley reduces the effort required to lift a heavy load.

physics machines levers and pulleys pulley pulleys

  1. True

  2. False

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Correct Option: A

A pulley makes our work easier by changing the direction of the force.

physics machines levers and pulleys pulley pulleys

  1. True

  2. False

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Correct Option: A

Levers, inclined planes and pulleys are called:

physics common machines levers and pulleys pulley pulleys

  1. Compound machines

  2. Complex machines

  3. Easy machines

  4. Simple machines

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Correct Option: D
Explanation:
  1. A simple machine is a mechanical device that changes the direction or magnitude of a force. In general, they can be defined as the simplest mechanisms that use mechanical advantage (also called leverage) to multiply force. Levers,inclined planes and pulleys are called simple machines