Question

Find the acceleration acquire by a car moving with velocity 40km/h and comes to rest in 5 minutes​

Answer 1

Solution:

Given:

$\tt\longrightarrow Initial\:Velocity\:(u)= 40km\:h^{-1}$

$\tt\longrightarrow Final\:Velocity\:(v)= 0km\:h^{-1}$

$\tt\longrightarrow Time\:Taken\:(t)=5\:min=300s$

We know that:

$\tt\longrightarrow Acceleration\:(a)=\dfrac{v-u}{t}$

Therefore:

$\tt\longrightarrow a=\dfrac{(0-40)km\:h^{-1}}{300\:s}$

$\tt\longrightarrow a=\dfrac{-40\:km\:h^{-1}}{300\:s}$

$\tt\longrightarrow a=\dfrac{-40\times \dfrac{5}{18}\:ms^{-1}}{300\:s}$

$\tt\longrightarrow a=\dfrac{-200}{18\times 300}ms^{-2}$

$\tt\longrightarrow a=-0.037\:ms^{-2}$

Which is our required answer. Negative sign indicates that the motion of the body is retarded.

Answer:

• The acceleration of the car is -0.037 m/s²

Learn More:

Equations of motion.

$\tt1.\:\:v=u+at$

$\tt2.\:\:S=ut+\dfrac{1}{2}at^2$

$\tt3.\:\:v^2=u^2+2aS$

Where:

$\tt\longrightarrow u=Initial\:Velocity$

$\tt\longrightarrow v=Final\:Velocity$

$\tt\longrightarrow a=Acceleration$

$\tt\longrightarrow t=Time\:Taken$

$\tt\longrightarrow S=Displacement$