Question

A driver decreases the speed of a car from 25 m/s to 10 m/s in 5 seconds. Find the acceleration of the car?

Answer 1

Answer:

-3 m/s^2

Explanation:

u = 25, v = 10, t = 5

Acceleration = v - u / t

= 10 - 25 / 5

= -15 / 5

= -3 m/s^2

Answer 2

Required Solution:

Given:

• Initial velocity (u) = 25m/s

• Final velocity (v) = 10m/s

• Time taken (t) = 5 s

To calculate:

• Acceleration (a)

Calculation:

We know that,

• ${\underline {\underline {\boxed{\Large {\rm { a = \dfrac{v-u}{t} }}}}} }$

Substitute the values:

$\sf { ⇢ a = \dfrac{10-25}{5}}$

$\sf { ⇢ a = \dfrac{-15}{5}}$

$\sf { ⇢ a = -3m/{s}^{2} }$

Therefore,acceleration of the car is 3m/s².

[ Note : Negative sign indicates retardation. ]

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Related Information:

• Acceleration is the rate of change in velocity over time.

• It is a vector quantity.

Formula: ${\underline {\underline {\boxed{\Large {\rm { a = \dfrac{v-u}{t} }}}}} }$

• SI unit of acceleration is m/s².

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Equations of motion:

• v = u + at

• s = ut + ½at²

• v² - u² = 2as

Where,

※ v = final velocity = m/s

※ u = initial velocity = m/s

※ a = acceleration = m/s²

※ s = distance/displacement = m

※ t = time = seconds

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