Question

when a car travel at a speed of 60km/he applies brake it comes to rest in 15s then the retardation of the car is​

Answer 1

Answer:

$\blue{\bold{\underline{\underline{Answer:-}}}}$

Given

• a car travel at a speed of 60 km/h applies brake it comes to rest in 15 s

To Find

• Retardation of the car

Concept Used

• Retardation and acceleration are both same but opposite in direction

Solution

Initial velocity , u = 60 km/h = 16.67 m/s²

Final velocity , v = 0 m/s

Since , finally comes to rest

Time , t = 15 s

Acceleration , a = ? m/s²

Apply 1st equation of motion ,

⇒ v = u + at

⇒ (0) = (16.67) + a(15)

⇒ 15a = -16.67

⇒ a = -1.12 m/s² 

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Answer 2

$\huge\sf\pink{Answer}$

☞ Retardation = 1.106 m/s²

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$\huge\sf\blue{Given}$

✭ Initial Velocity = 60 km/h

✭ Final Velocity = 0 km/h

✭ Time = 15 sec

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

◈ Acceleration of the car(Negative Acceleration)?

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$\huge\sf\purple{Steps}$

So here we shall use the first equation of motion, that is,

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

So here before substituting the values we have to convet the speed to m/s.

➝ $\sf Speed = \dfrac{60\times 1000}{60\times 60}$

➝ $\sf Speed = 16.6 \ m/s$

So substituting the given Values in the formula,

»» $\sf v = u+at$

»» $\sf 0 = 16.6+a\times 15$

»» $\sf -16.6 = 15a$

»» $\sf \dfrac{-16.6}{15} = a$

»» $\sf \orange{a = -1.106 \ m/s^2}$

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