Tag: pulleys

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Questions Related to pulleys

Multiple choice physics machines levers and pulleys pulley pulleys

In a fixed pulley 

  1. load and effort are equal

  2. load is greater than effort

  3. load is less than effort

  4. both have no relation
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In a single fixed pulley, the effort applied equals the load being lifted, as the mechanical advantage is 1.

Multiple choice physics machines levers and pulleys pulley pulleys

A block and tackle system has the velocity ratio $3$. A man can exert a pull of $200kgf$. What is the maximum load he can raise with this pulley system if its efficiency is $60\%$

  1. $250 kgf$

  2. $260 kgf$

  3. $350 kgf$

  4. $360 kgf$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$Mechanical advantage = Velocity Ratio \times Efficiency $
$M.A = 3 \times \dfrac{60}{100} = 1.8$
$M.A = \dfrac{load}{effort} $
$\therefore load = M.A \times effort$
$\Rightarrow 1.8 \times 200 = 360kgf$

Multiple choice physics machines levers and pulleys pulley pulleys

It is easy to draw water from a well when the rope passes over a pulley than drawing it directly. Because:

  1. pulley adds more force

  2. pulley decreases the weight of the bucket

  3. pulley has a mechanical advantage of more than one

  4. pulley changes the direction of force
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A fixed pulley does not reduce the weight or add force; it simply changes the direction of the force, allowing the user to use their body weight to pull down instead of lifting up.

Multiple choice physics machines levers and pulleys pulley pulleys

A force of $250 N$ is required to lift a $75 kg$ mass through a pulley system. In order to lift the mass through $3 m$, the rope has to be pulled through $12m$. The percent efficiency of system is

  1. $50$

  2. $75$

  3. $33$

  4. $90$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Height lift was $h=3m$
Work done by the force is $W=Fd=250\times 12=3000Joule$

Work against the gravity i.e. $increase $ in potential energy of the  mass is $E=mgh=75\times 10\times 3=2250Joule $

so efficiency will be $\eta \times 100=\dfrac{E}{W}\times 100$% = $75$%

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

By using a wheel-and-axle arrangement,you can :

  1. Magnify the speed

  2. Magnify movement

  3. Effort can be moved through a greater distance by attaching a handle

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A wheel and axle is a simple machine that can be used to increase speed, increase force, or change the distance over which effort is applied. Since all these are valid functions of the arrangement, the all-of-the-above option is correct.

Multiple choice physics machines levers and pulleys pulley pulleys

It is easy to draw water from a well when the rope passes over a pulley than drawing it directly. Because :

  1. Pulley adds more force

  2. Pulley decreases the weight of the bucket

  3. Pulley has a mechanical advantage of more than one

  4. Pulley changes the direction of force
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A single fixed pulley does not provide a mechanical advantage greater than one, nor does it reduce the weight of the load. Its primary purpose and advantage in this context is changing the direction of the applied force, making it more convenient to pull downward.