Question

A car traveling at 15 m/s starts to decelerate steadily. It comes to a complete stop in 10 seconds.
What is it’s acceleration?

Answer 1

Acceration= Speed/Time

$a = \frac{15}{10} = 1.5$

As the car stopped, it is negative acceleration so we will write it as -1.5m/s².

Acceration= -1.5m/s²

Answer 2

Answer:

Initial velocity (u) = 15 m/sec

Final velocity (v) = 0

Time (t) = 10 seconds

Using 1st Equation of motion :

v = u + at

0 = 15 + a × 10

0 = 15 + 10a

10a = -15

a = -15/10

a = -1.5 m/sec^2

Acceleration = -1.5 m/sec^2

Retardation = 1.5 m/sec^2 ANSWER.

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