Question

when a car travel at a speed of 60km/he applies brake it comes to rest in 15s then the retardation of the car is​

Answer 1

Answer:

10/9m/s2

Explanation:

acceleration is given by

$a=\frac{\Delta{v}}{\Delta{t}}$

$\Delta v=60km/h=\frac{50}{3} m/s$

Delta t=15 sec

$a=\frac{\Delta{v}}{\Delta{t}}\\\\a=\frac{50}{15*3}\\\\a=\frac{10}{9}m/s^2$

Answer 2

Answer

Retardation of the car = 1.12 m/s²

Given

a car travel at a speed of 60 km/h applies brake it comes to rest in 15 s

To Find

Retardation of the car

Concept Used

Retardation and acceleration are both same but opposite in direction

Solution

Initial velocity , u = 60 km/h = 16.67 m/s²

Final velocity , v = 0 m/s

Since , finally comes to rest

Time , t = 15 s

Acceleration , a = ? m/s²

Apply 1st equation of motion ,

⇒ v = u + at

⇒ (0) = (16.67) + a(15)

⇒ 15a = -16.67

⇒ a = -1.12 m/s² $\pink{\bigstar}$

Note : Negative sign of acceleration denotes retardation

So , Retardation of the car = 1.12 m/s²