Question

A car is moving at a peed of 18km/h. It satarts retarding uniformly at 1m/s2 and comes to rest. Find the distance trtaveled

Answer 1

Answer:

12.5 m

Explanation:

According to the given question,

u = initial velocity = 18 km/h = 18×1000/3600 = 5 m/s

v = final velocity = 0 m/s

s = displacement and a = acceleration

and -a = deceleration = 1m/s^2

And we asked to find the distance travelled.

Here distance is equal to the displacement as it's linear motion, without changing it's direction.

We know,

• v^2=u^2+2as

Putting the values we get,

• 0 = 25-2×1×s

• -25 = -2s

• 2s = 25

• s = 25/2

• s = 12.5 m

Thus distance travelled is 12.5 m from the given condition.

Answer 2

Answer:

$\large{\underline{\boxed{\sf Distance = 12.5 \: m}}}$

Explanation:

Given that ;

A car is moving at a speed of 18 km/h. Now, convert km/h into m/s.

⇒ Initial velocity (u) = 18 * 5/18

⇒ Initial velocity = 5 m/s

Then, car comes to rest.

⇒ Final velocity (v) = 0 m/s

The car starts retarding at 1 m/s²

⇒ Deceleration (-a) = 1 m/s²

_______________________

To find the distance travelled, we will use third equation of motion here;

v² - u² = 2as

⇒ 0² - 5² = 2 * (-1) * s

⇒ - 25 = - 2s

⇒ s = $\sf \dfrac{25}{2}$

⇒ s = 12.5 m

Hence, the distance travelled by car is 12.5 metres.