Tag: levers and pulleys

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Questions Related to levers and pulleys

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

Two crowbars of lengths 5 m and 7 m are used to lift a boulder, using a small stone, as a fulcrum. Does it affect the effort required to lift the load?

  1. Yes

  2. No

  3. Maybe

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

Yes it effects the effort required to lift the load as a crow bar of 7 m length provides greater effort arm than a crow bar of 5 m length. Thus crow bar of 7 m length requires lesser effort.

Multiple choice physics machines levers and pulleys pulley pulleys

A block of mass M on a horizontal smooth surface is pulled by a load of mass  M / 2  by means of a rope  AB and string BC as shown in the figure .The length and mass of the rope AB are L and  M / 2 respectively .As the block is pulled from A = L to AB = 0 its acceleration changes from 

  1. $\frac{3g}{4}$ to g

  2. $\frac{g}{4} to\frac {g}{2}$

  3. $\frac{g}{4} to {g}$

  4. $\frac{3g}{2}$ to 2g
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice physics machines levers and pulleys pulley pulleys

What is the ideal mechanical advantage of a single fixed pulley? Can it be used as a force multiplier?

  1. $1.5$, yes

  2. $1.5$, No

  3. $1$, yes

  4. $1$, No
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A single fixed pulley has an ideal mechanical advantage of 1 since the effort force is equal to the load force.
No, it cannot be used as a force multiplier, instead, it is used to change the direction of force applied.

Multiple choice physics machines levers and pulleys pulley pulleys

$1000$ N force is required to lift a hook and $10000$ N force is requires to lift a load slowly. Find power required to lift hook with load with speed $v = 0.5 m/sec$

  1. $5kw$

  2. $5.5kw$

  3. $1.5kw$

  4. $4.5kw$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$P=F.V=(1000+1000)0.5$
$=\dfrac{11000}{2}=5500=5.5kw$

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

The machine used to separate the massive particles and light particles from a mixture is

  1. At wood machine

  2. Centrifugation

  3. Filter paper

  4. Separating funnel
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Centrifugation is the process of separating suspended particles from a liquid by rotating the liquid at a high speed. The mixture is taken in a closed bottle and rotated at a high speed. The heavy particles settle at the bottom while light particles remain behind. This method is used to separate cream from milk

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 force

  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 can be used to magnify force (if input is on the wheel), increase speed (if input is on the axle), or provide mechanical advantage through handle length.

Multiple choice physics machines levers and pulleys pulley pulleys

A pulley system has a velocity ratio $3$ and an efficiency of $80\%$. Calculate the effort required to raise a load of $300N$.

  1. $125 N$

  2. $300 N$

  3. $150 N$

  4. $225 N$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
$Velocity\ Ratio = 3$

$Efficiency = 80/100$

$Mechanical \ Advantage = efficiency \times Velocity\  ratio$

$\Rightarrow \dfrac{80}{100} \times 3 $

$\Rightarrow 2.4$


$M.A = \dfrac{load}{effort}$

$2.4 = \dfrac{300 N}{Effort}$

$\Rightarrow Effort = \dfrac{300 N}{2.4} = 125N$

Multiple choice physics machines levers and pulleys pulley pulleys

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

  1. $2x$

  2. $x$

  3. $x/2$

  4. $x/g$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

We know that for a single fixed pulley, Distance moved by effort is equal to the distance moved by load.
$ Distance\; moved \;by\; effort = x$
$\therefore Distance \;moved \;by \;load = x$

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

A car steering is an example of :

  1. first order lever

  2. second order lever

  3. complex machine

  4. wheel-and-axle
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A car steering wheel is a classic example of a wheel-and-axle, where the large wheel provides mechanical advantage to turn the smaller steering column (axle).

Multiple choice physics machines levers and pulleys pulley pulleys

A pulley system has a velocity ratio $3$ and an efficiency of $80\%$. Calculate the mechanical advantage of the system.

  1. $2.0$

  2. $3.0$

  3. $2.4$

  4. $1.4$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$Velocity\ Ratio = 3$


$Efficiency = 80/100$

$Mechanical \ Advantage = efficiency \times Velocity\  ratio$

$\Rightarrow \dfrac{80}{100} \times 3 $

$\Rightarrow 2.4$