Question

if a bus decrease it's speed from 60 km /hr to 40/hr in 5sec find its acceleration
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Answer 1

Answer:

u= initial velocity= 80 km/h = 22.2 m/s v= final velocity 60 km/h = 16.7 m/s

t= time = 5 s

a= acceleration = ?

a=v-u/t

a= 16.7-22.2/5

a= -5.5/5

Therefore, a=-1.1 m/s^2

Answer 2

$\huge\sf\pink{Answer}$

☞ Acceleration = -4 km/s²

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$\huge\sf\blue{Given}$

✭ Initial Velocity (u) = 60 km/h

✭ Final Velocity (v) = 40 km/h

✭ Time (t) = 5 sec

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$\huge\sf\gray{To \:Find}$

◈ The Acceleration?

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$\huge\sf\purple{Steps}$

Here we shall use the first law of motion,that is

$\underline{\boxed{\red{\sf v = u+at}}}$

Where,

◕ v = Final Velocity

◕ u = Initial Velocity

◕ t = Time

◕ a = Acceleration

Substituting the given values,

➳ $\sf 40 = 60+a\times 5$

➳ $\sf 40-60 = a\times 5$

➳ $\sf -20 = 5a$

➳ $\sf\dfrac{-20}{5} = a$

➳ $\sf\orange{a = -4 \ Km/s^2}$

❍ $\green{\sf Addition \ Information}$

»» Acceleration is a vector quantity

»» Rate of change of acceleration is called acceleration

»» Acceleration is defined as the slope of time-velocity graph

Equations of Motion are

➝ v = u+at

➝ s = ut+½ at²

➝ v²-u² = 2as

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