Question

A car decreases its speed from 90km/h to 54 km/h in 5 seconds .Find the acceleration of the car.

Answer 1

Answer:

Given :-

• A car decreases it's speed from 90 km/h to 54 km/h in 5 seconds.

To Find :-

• What is the acceleration of the car.

Formula Used :-

$\clubsuit$ Acceleration Formula :

$\longmapsto \sf\boxed{\bold{\pink{a =\: \dfrac{v - u}{t}}}}$

where,

• a = Acceleration
• v = Final velocity
• u = Initial velocity
• t = Time

Solution :-

Given :

$\mapsto\sf Initial\: velocity\: =\: 90\: km/h =\: 90 \times \dfrac{5}{18} =\: 25\: m/s$

$\mapsto \sf Final\: velocity =\: 54\: km/h =\: 54 \times \dfrac{5}{18} =\: 15\: m/s$

$\mapsto\sf Time =\: 5\: seconds$

According to the question by using the formula we get,

$\dashrightarrow \sf a =\: \dfrac{15 - 25}{5}$

$\dashrightarrow \sf a =\: \dfrac{- \cancel{10}}{\cancel{5}}$

$\dashrightarrow \sf\bold{\red{a =\: - 2\: m/s^2}}$

$\therefore$ The acceleration of the car is - 2 m/s².

[Note : The negetive (- ve) signs indicate that the velocity is decreasing. ]