Question

computer calculated mean and standard deviation from 20 observations as 42 and 5 respectively. It was later discovered at the time of checking that it had copied down two values as 45 and 38, whereas the correct values were 35
and 58. Find correct value of coefficient of variation.​

Answer 1

Answer:

Given :

A car retards uniformly at the rate of 5 m/s² and stops in 10 s.

To Find :

Initial Velocity of the car .

Solution :

\longmapsto\tt{Retardation\:(a)=-5\:{m/s}^{2}}⟼Retardation(a)=−5m/s

2

\longmapsto\tt{Final\:Velocity(v)=0\:m/s}⟼FinalVelocity(v)=0m/s

\longmapsto\tt{Time\:Taken=10\:sec}⟼TimeTaken=10sec

Using 1st Equation :

\longmapsto\tt\boxed{v=u+at}⟼

v=u+at

Putting Values :

\longmapsto\tt{0=u+(-5)\times{10}}⟼0=u+(−5)×10

\longmapsto\tt{-u=-50}⟼−u=−50

\longmapsto\tt\bf{u=50\:m/s}⟼u=50m/s

So , The Initial Velocity of car is 50 m/s .

Option c) 50 m/s is Correct .

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Three Equations Of Motion :

v = u + at

s = ut + 1/2 at²

v² - u² = 2as

Here :

v = Final Velocity

u = Initial Velocity

t = Time Taken

a = Acceleration

s = Distance Travelled

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