Tag: pulley

Questions Related to pulley

In a pulley:

physics machines levers and pulleys pulley pulleys

  1. Wheel is fixed over the axle

  2. Direction of force will not be changed

  3. Mechanical advantage will be more than one

  4. Wheel rotates freely over the axle

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Correct Option: D

______ is used to pull water from a well.

physics machines levers and pulleys pulley pulleys

  1. Pulley

  2. Lever

  3. Gears

  4. None of the above

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Correct Option: A

Velocity ratio of a single movable pulley is

physics machines levers and pulleys pulley pulleys

  1. 1

  2. 0

  3. 2

  4. None

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Correct Option: C
Explanation:

$\displaystyle VR=\frac { Distance\quad moved\quad by\quad effort }{ Distance\quad moved\quad by\quad load } $
$\displaystyle MA=\frac { 2Effort }{ Effort } =2$
When effort mved a distance x load moved a distance = x/2
So, 
$\displaystyle VR=\frac { X }{ X12 } =\frac { 2X }{ X } =2$

Single movable pulley acts as a

physics machines levers and pulleys pulley pulleys

  1. speed multiplier

  2. force multiplier

  3. velocity multiplier

  4. all

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Correct Option: B
Explanation:

Using a single movable pulley, the load can be lifted by applying an effort equal to half the load i.e. single movable pulley acts as a force multiplier.

Which of the following is not fixed to a rigid support?

physics machines levers and pulleys pulley pulleys

  1. Single fixed pulley

  2. Single movable pulley

  3. Double fixed pulley

  4. None

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Correct Option: B
Explanation:

Single fixed pulley is fixed to a rigid support whereas a single movable pulley is not fixed to a rigid support.

Weight of the pulley ____ the mechanical advantage of single fixed pulley and ____ the mechanical advantage of single movable pulley 

physics machines levers and pulleys pulley pulleys

  1. increases, increases

  2. increases, reduces

  3. doesn't affect, reduces

  4. reduces, does not affect

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Correct Option: C
Explanation:

Weight of pulley does not affect mechanical advantage of single fixed pulley.

Weight of pulley reduces mechanical advantage of single fixed pulley(because it is not stationary).

In single movable pulley,

physics machines levers and pulleys pulley pulleys

  1. Ideal mechanical advantage is 1.

  2. Load moves in the direction of effort

  3. Velocity ratio is 1

  4. All

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Correct Option: B
Explanation:

In single movable pulley, ideal mechanical advantage is 2. Its velocity ratio is 2. It is used as a force multiplier. Load moves in the direction of effort.

Pulley whose axis of rotation is not fixed at a position is called

physics machines levers and pulleys pulley pulleys

  1. Single fixed pulley

  2. Movable pulley

  3. Both

  4. None

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Correct Option: B
Explanation:

A movable pulley is a pulley allowed to have translational motion.

State true or false.
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

Calculate the effort in newtons required to raise 1000 kg anchor on boat with a wheel and axle of radii 50 cm and 10 cm respectively.

physics a little effort, lot of work levers and pulleys pulley pulleys

  1. 1000

  2. 1500

  3. 2000

  4. 3000

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Correct Option: C
Explanation:

The mechanical advantage of a wheel and axle $= \displaystyle \frac{Radius  of  wheel}{Radius  of  the  axle} $      ..........  (1)
But $MA = \displaystyle \frac{load}{effort}$      .............    (2)
From (1) and (2)
$\displaystyle \frac{Radius  of  wheel}{Radius  of  the  axle} = \frac{load}{effort}$
$\displaystyle \frac{50  cm}{10  cm} = \frac{1000 \times  10  N}{effort}$
$Effort = \displaystyle \frac{1000  \times  10  \times 10}{50}$
$ Effort = 2000 N$