Question

The brakes of a car traveling at 72 kmph are applied steadily and cause uniform acceleration. If the car stops in 4 s, how far did it travel before it comes to rest?

Answer 1

Answer:

40 m

Explanation:

Answer 2

The car traveled 40 m before it came to rest.

Explanation:

Given

Speed of the car = 72 kmph = 72 × (5/18) = 20 m/s

The car stops in 4 seconds

The final peed of car = 0

From the first equation of motion

$v=u+at$

Here

v = 0

u = 20 m/s

t = 4 s

a = ?

$0=20+a\times 4$

$a=-5$ m/s²   (negative sign indicates retardation)

If the distance travelled is s

Then, from the third equation of motion

$v^2=u^2+2as$

$\implies 0^2=20^2+2(-5)s$

$\implies s=\frac{20\times 20}{10}$ m

$\implies s=40$ m

Hope this answer is helpful.

Know More:

Q: A driver of a car travelling at 52 kilometre per hour applies the brakes and accelerates uniformly in the opposite direction. the car stops in 5 seconds .another driver going at 3 kilometre per hour in another car applies is break slowly and stop in 10 seconds. on the same graph paper clock speed versus time graph for the two cars. which of the car travel father after the brakes are applied?

Click Here: https://brainly.in/question/1167123