1.

Two blocks of mass 20 kg and 10 kg are connected by a massless string as shown in the figure. How much time will 20 kg block take to travel 0,6 m distancewhen released from rest?[Take gravitational acceleration as 10 m/s2]​

Answer»

Answer:

\huge{\underline{\dag{Given:}}}

Mass of two blocks which are connected to massless string:

>>> 20 kg and 10 kg

DISTANCE travel by the 20 kg block:

>>> 0.6 m

Acceleration due to gravity:

>>> 10 m/s²

INITIAL velocity:

>>> 0

\huge{\underline{\dag{To\:find:}}}

Time TAKEN to travel

\huge{\underline{\dag{Taken:}}}

First find the acceleration of the both block with the massless string:

a\implies \bold {  \frac{m1 - m2}{m1 + m2} }

Where,

a = Acceleration

m1 = Mass of the FIRST block

m2 = Mass of the second block

And then use the second equation of MOTION to find the time taken:

\bold{ s =ut +  \frac{1}{2} a {t}^{2} }

Where,

s = Distance travelled

ut = Initial velocity

a = Acceleration

t = Time taken

\huge{\underline{\dag{Concept:}}}

To find the acceleration subtract mass of 1 st block with the acceleration due to gravity like this :

a \implies \bold{ \frac{(m1 - g)m2}{m1 + m2} }

Where,

a = Acceleration

m1 = Mass of the first block

m2 = Mass of the second block

g = Acceleration due to gravity

\huge{\underline{\dag{Solution:}}}

First , acceleration:

\bold\purple{Taken,a=\frac{(m1-g)m2}{m1+m2}}

\bold{a=\frac{(20kg-10m/s)10}{20kg+10kg}}

\bold{a=\frac{10×10}{30}}

\bold{a=\frac{10}{3}}

___________________________________

Now , find the time taken:

\bold\purple{Taken,s=ut+\frac{1}{2}at²}

\bold{0.6m=0+\frac{1}{2}×\frac{10}{3}×t²}

\bold{t²=\frac{3.6}{10}}

\bold{t²=\frac{36}{100}}

\bold{t =  \sqrt{ \frac{36}{100} } }

\bold{t =  \frac{6}{10} }

\bold{t=0.6}

\huge{\underline{\dag{Answer:}}}

So , the time taken by the first block is 0.6 seconds .

\huge{\underline{\dag{Extra\:information:}}}

First equation of motion:

\bold{Vf=Vi+at}

Where,

Vf = Final velocity

Vi = Initial velocity

a = Acceleration

t = Time

Third equation of motion:

\bold{v²-u²=at}

Where,

v² = Final velocity

u² = Initial velocity

a = Acceleration

t = Time

Fourth equation of motion:

\bold{v²=u²+2as}

Where,

v² = Final velocity

u² = Initial velocity

a = Acceleration

HOPE IT HELPS YOU



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