Question

A driver applies the brakes and slow down the velocity of the bus from 80 kmh-1 to 60 km-1 in 5 sec. calculate the acceleration of the bus.​

Answer 1

Solution

Given :

Initial velocity of bus (u)  = 80 kmh⁻¹ = 200/9 m/s

Final velocity of bus (v) = 60 kmh⁻¹  = 50/3 m/s

Time taken = 5 sec.

                                                   

To find :

Acceleration

                                                 

According to the question

we have to use formula of

acceleration.

                                                     

Acceleration = $\dfrac{Final-Initial\:velocity}{Time\:Taken}$

                                     

                                  Or

= $\dfrac{v-u}{t}$

                                                           

Let us solve

$\implies\dfrac{\dfrac{50}{3}-\dfrac{200}{9}}{5}\\\\\\\\=\dfrac{\dfrac{150-200}{9}}{5}\\\\\\\\=\dfrac{\dfrac{-50}{9}}{5}\\\\\\\\=\dfrac{-50}{9}\times\dfrac{1}{5}\\\\\\\\=-\dfrac{10}{9}\\\\\\\\=-1.11\:m/s^2\:(approx)$

                                                   

Answer = - 1.11 m/s² (approx)

Answer 2

Given:

Initial Velocity, u = 80 km/h = 22.22 m/s

Final Velocity, v = 60 km/h = 16.66

Time, t = 5 sec

Acceleration, a = ?

We know,

$\boxed{a = \dfrac{v-u}{t}}$

$a = \dfrac{16.66 - 22.22}{5} \\ a = \dfrac{-5.56}{5} \\ \bold{a = -1.112}$

Therefore, acceleration of the bus is$\bold{-1.112 m/s^{2}}$