Question

A car is moving at a speed of 18km/hr it starts retarding uniformly at 1m/s^2 and comes at rest find the distance travelled

Answer 1

ans: 5metres

explanation :

18 km/hr = 5 m/s =u

v = 0

a =-1 m/s^2

a = v-u / t

t = 5 sec

s = u /t

s =5 m/s / 5 s

s=5metres

Answer 2

Answer:

$\large\boxed{\sf{12.5\;m}}$

Explanation:

Given that,

A car is moving at a speed of 18 Km/hr.

It starts regarding uniformly at 1m/s^2.

To find the distance travelled.

Let the initial velocity = u

Final velocity = v

Acceleration = a

Distance travelled = s

So, Clearly, we have,

$= > u = 18 \times \frac{5}{18} \\ \\ = > u = 5 \: m {s}^{ - 1}$

Now, since the car retards and finally comes to rest.

Therefore, we have,

$= > v = 0 \: m {s}^{ - 1}$

Also, since there is retardation,

Therefore, we have,

$= > a = - 1 \: m {s}^{ - 2}$

Now, we know that,

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

Therefore, substitute the respective values,

We will get,

$= > {0}^{2} = {5}^{2} + 2( - 1)s \\ \\ = > 0 = 25 - 2s \\ \\ = > 2s = 25 \\ \\ = > s = \frac{25}{2} \\ \\ = > s = 12.5 \: m$

Hence, the distance travelled = 12.5 m