Tag: machines

Questions Related to machines

A pulley can reduce the effort needed to overcome a particular load 

  1. True

  2. False


Correct Option: A

Single fixed pulley has an mechanical advantage of

  1. 1

  2. 0

  3. 2

  4. 100


Correct Option: A
Explanation:

A sing;e fixed pulley like the one having an ideal mechanical advantage of 1 since the effort force is equal to the load force.

In a pulley:

  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


Correct Option: D

______ is used to pull water from a well.

  1. Pulley

  2. Lever

  3. Gears

  4. None of the above


Correct Option: A

Velocity ratio of a single movable pulley is

  1. 1

  2. 0

  3. 2

  4. None


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

  1. speed multiplier

  2. force multiplier

  3. velocity multiplier

  4. all


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?

  1. Single fixed pulley

  2. Single movable pulley

  3. Double fixed pulley

  4. None


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 

  1. increases, increases

  2. increases, reduces

  3. doesn't affect, reduces

  4. reduces, does not affect


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,

  1. Ideal mechanical advantage is 1.

  2. Load moves in the direction of effort

  3. Velocity ratio is 1

  4. All


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

  1. Single fixed pulley

  2. Movable pulley

  3. Both

  4. None


Correct Option: B
Explanation:

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