Question

a driver decrease the speed of a car from 50m/s to 20m/s in 10 sec find the acceleration of the car ​

Answer 1

Answer:

• Acceleration is -3 m/s².

Given:

• Initial velocity (u) = 50 m/s
• Final velocity (v) = 20 m/s
• Time taken (t) = 10 sec

Explanation:

$\rule{300}{1.5}$

Here, we are given that a driver decreases the speed of a car from 50 m/s to 20 m/s in 10 sec. We are asked to find out the acceleration of the car.

From first kinematic equation we know,

$\longrightarrow{\sf{v\ =\ u\ +\ at}}$

Substitute the values,

$\longrightarrow{\sf{20\ =\ 50\ +\ a \times 10}} \\ \\ \\ \longrightarrow{\sf{20\ -\ 50\ =\ 10a}} \\ \\ \\ \longrightarrow{\sf{-30\ =\ 10a}} \\ \\ \\ \longrightarrow{\sf{\dfrac{-30}{10}\ =\ a}} \\ \\ \\ \longrightarrow{\sf{-3\ =\ a}} \\ \\ \\ \longrightarrow{\sf{a\ =\ -3\ m/s^2}}$

∴ The acceleration of the car is -3 m/s² [Here -ve sign shows retardation].

$\rule{300}{1.5}$