Question

A car travelling with a velocity of 80km/h slowed down to 44 km/h in 15 sec.The retardation is

Answer 1

u=80km/h=22m/s
v=44km/h=12m/s
t=5sec
v=u+at
12=22+a×5
-10/5= a
here a is retardation

Answer 2

Answer:

A car traveling with a velocity of 80km/h slowed down to 44 km/h in 15 sec. The retardation is $0.66666\ m/s^2$

Explanation:

Acceleration is given by the expression,

$a = \frac{v-u}{t}$                 ...(1)

where u is the initial velocity of the object, v is the final velocity and t is the time taken.

Or Acceleration (a) of an object can be defined as the rate of change of velocity with respect to time.

In the question, it is given that,

$u = 80\ km/h = 80\times \frac{5}{18} = 22.2222\ m/s$

$v = 44\ km/h = 44\times \frac{5}{18} = 12.2222\ m/s$

$t = 15\ s$

Substitute these values into the equation(1)

$a = \frac{12.2222- 22.2222}{15} = -0.66666\ m/s^2$

The retardation of the car = $0.66666\ m/s^2$