Tag: introduction to simple machines

Quizzes (0) Questions (120)

Questions Related to introduction to simple machines

Multiple choice physics simple machine common machines terms related to machines introduction to simple machines

It is easier to draw up a wooden block along an inclined plane than to haul it vertically, principally because:

  1. the friction is reduced

  2. the mass becomes smaller

  3. only a part of the weight has to be overcome

  4. $g$ becomes smaller
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The vertical plane $W=mgh$
for inclined plane $W'=mghsin(Q)$
$sinQ<1$
$W>W'$
hence only one part of weight is to overcome

Multiple choice physics simple machine common machines terms related to machines introduction to simple machines

A pump ejects $12000\ kg$ of water at the speed of $4\ { m }/{ s }$ in $40\ second.$ Find the average rate at which the pump is working

  1. $2.4kw$

  2. $2.5kw$

  3. $2.3kw$

  4. $1.7kw$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
$F=ma=12000\times \dfrac {4}{40}=1200\ N$
$A=F/m=1200/1200=1/10\ m/s^2$
$s=ut +\dfrac {1}{2}at^2=0+\dfrac {1}{2}\times \dfrac {1}{10}\times 40\times 40=80\ m$
then, $W=Fs=80\times 1200=96000\ J$
rate of working, $P=\dfrac {W}{t}$
$P=\dfrac {96000}{40}=2400W=2.4\ kW$
Multiple choice physics simple machine common machines terms related to machines introduction to simple machines

The mechanical advantage of inclined plane of angle of inclination $60^{\circ}$ is equal to :

  1. $\dfrac{2}{\sqrt{3}}$

  2. $cosec 30^o$

  3. both (1) and (2)

  4. none of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Mechanical advantage of an inclined plane at an angle $\theta$ is  $ \dfrac{Length }{height}$$ = \dfrac{l}{h} = \dfrac{1}{sin \theta}$


$ = cosec \theta = cosec 60^o = \dfrac{1}{sin 60^o} = \dfrac{2}{\sqrt{3}}$

Multiple choice physics lever common machines terms related to machines introduction to simple machines

Akhil has to lift a load of 800 N onto a platform of 2 m height. Instead, he pushes the load up a ramp 4 m long. Find the force required to roll the load up the ramp.

  1. 200 N

  2. 600 N

  3. 400 N

  4. 800 N
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Force required to roll the load up the ramp (F) $=\displaystyle \frac{load \times height}{distance}$
$= 800 \displaystyle \times \frac{2}{4} = 400 N$

Multiple choice physics lever common machines terms related to machines introduction to simple machines

The ratio of the radius of two wheels A and B are in the ratio 3 : 7 respectively and the ratio of their respective axles is 5 : 4. Identify the wheel and axle that has greater mechanical advantage?

  1. A

  2. B

  3. Both have same

  4. Can't say
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The mechanical advantage of a wheel and axle $= \displaystyle \frac{Radius \ of \ wheel}{Radius \ of \ the \ axle}$
$MA _A = \displaystyle \frac{R _1}{r _1} $ and  $MA _B = \displaystyle \frac{R _2}{r _2}$
Given $ r _1  :  r _2  = 5 : 4$
$R _1  :  R _2  = 3  :  7$
$ \displaystyle \frac{MA _A}{MA _B} = \frac{R _1}{r _1} \times \frac{r _2}{R _2}$
$\displaystyle = \frac{3}{5} \times \frac{4}{7} = \frac{12}{35}$
$MA _B >  MA _A$

Multiple choice physics lever common machines terms related to machines introduction to simple machines

In a wheel-axle arrangement, the radius of wheel is 25 times more than the radius of an axle. Find the mechanical advantage of the machine.

  1. 20

  2. 25

  3. 30

  4. 35
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The mechanical advantage of a wheel and axle $= \displaystyle \frac{Radius  of  wheel}{Radius  of  the  axle}$
Given radius of wheel $=$ 25 $\times$ radius of axle
$MA = \displaystyle \frac{25 \times radius  of  axle}{radius  of  axle} = 25$

Multiple choice physics lever common machines terms related to machines introduction to simple machines

Which of the following statements in NOT correct?

  1. In a first order lever, the fulcrum is placed between the effort and the load.

  2. The mechanical advantage of a second class levers is greater than 1 as load is situated in between to effort and fulcrum.

  3. An inclined plane in a hospital, helps in pushing a wheel chair easily.

  4. A crow bar is an example of second class level.
Reveal answer Fill a bubble to check yourself
A,B,C Correct answer
Multiple choice physics lever common machines terms related to machines introduction to simple machines

An effort of 20 kgf is applied on a machine through a distance of 80 cm, when a load of 30 kgf moves through a distance of 1 cm. Calculate the velocity ratio of the machine.

  1. 40

  2. 80

  3. 160

  4. 60
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Velocity ratio $= \displaystyle \frac{distance \ of \ the \ effort}{distance \ moved \ by \ the \ load}$
$= \displaystyle \frac{80  cm}{1  cm}= 80$

Multiple choice physics lever common machines terms related to machines introduction to simple machines

Akhil has to lift a load of 800 N onto a platform of 2 m height. Instead, he pushes the load up a ramp 4 m long. Find the work done by Akhil in lifting the load vertically up.

  1. 800 J

  2. 1600 J

  3. 400 J

  4. 200 J
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The work done by Akhil in lifting the load vertically up $=$ Force $\times$ height
$= 800 \times 2 = 1600 \ J$