Question

a car decreases its speed from 80km/hr to 60 km/hr in 5 seconds. find the acceleration of the car in SI unit​

Answer 1

$\bf{\red{\underline{Given:}}}$

Initial velocity,u = 80 km/hr =22.222 m/s

Final velocity,v = 60 km/hr = 16.667 m/s

Time taken,t = 5 sec

$\bf{\pink{\underline{To\;Find}}}$

Acceleration

$\bf{\blue{\underline{Solution:}}}$

$\boxed{\green{a =\frac{v-u}{t}}}$

Now, putting values in above formula, we get:

$\sf{\implies a =\frac {16.667-22.222}{5}}$

$\sf{\implies a =\frac {-5.555}{5}}$

$\sf{\implies a = -1.111m/{s}^{2}}$

Hence,the acceleration will be

$\boxed{\boxed{\boxed { acceleration = -1.111 m/{s}^{2}}}}$

Answer 2

Given ,

• Initial velocity (u) = 80 km/h or 22.2 m/s
• Final velocity (v) = 60 km/h or 16.6 m/s
• Time (t) = 5 sec

We know that , the Newton's first equation of motion is given by

$\large \sf\fbox{v = u + at}$

Thus ,

16.6 = 22.2 + 5a

-5.6 = 5a

a = -5.6/5

a = -1.12 m/s²

$\sf \therefore \underline{The \: acceleration \: is -1.12 \: m/ {s}^{2} </p><p>}$