Question

a scooter acquires a velocity of 36 km/h in 10 seconds just after the start. it stops at 20 sec Calculate the acceleration of the scooter.

Answer 1

$\red{\bigstar}\underline{\underline{\textsf{\textbf{ Given :- }}}}$

• A scooter acquires a velocity of 36 km/h in 10 seconds just after the start.
• It stops in 20 seconds .

$\red{\bigstar}\underline{\underline{\textsf{\textbf{ To Find :- }}}}$

• The acceleration of the scooter .

$\red{\bigstar}\underline{\underline{\textsf{\textbf{ Solution :- }}}}$

We know that, acceleration is defined as the rate of change of velocity . Here the scooter starts from rest , therefore the initial Velocity of the scooter will be 0 . The final velocity of the scooter is 36km/hr = 5/18 * 36 m/s = 10m/s .

$\sf\dashrightarrow Accl^n =\dfrac{ \Delta v }{t} \\\\\\\sf\dashrightarrow Accl^n =\dfrac{ 10m/s - 0m/s}{10s} \\\\\\\sf\dashrightarrow Accl^n =\dfrac{10}{10} m/s^2 \\\\\\\sf\dashrightarrow\boxed{\pink{\frak{ Accl^n = 1\ m/s^2 }}}$

$\rule{200}2$

Now the scooter comes to rest in 20s . Hence the final velocity of the scooter is 0m/s . Since the velocity is decreasing , therefore the acclⁿ is negative and is called Retardation / Deacceleration .

$\sf\dashrightarrow Accl^n =\dfrac{ \Delta v }{t} \\\\\\\sf\dashrightarrow Accl^n =\dfrac{ 0m/s - 10m/s}{20s} \\\\\\\sf\dashrightarrow Accl^n =\dfrac{ -10}{20} m/s^2\\\\\\\sf\dashrightarrow \boxed{\pink{\frak{ Accl^n = -0.5\ m/s^2 }}}$