Question

Hey guys,

Plz help me.......

Answer 1

Hey there!

Given,

Distance (S) = 15 km = 15000 m

Time(t) = 20 min = 12* 60 sec = 1200 seconds

Now,

Speed = distance / time

           = 15000 / 1200

          = 12.5 m/s

Now,

In km / hr.

= 12.5 * 18/5 km/hr

= 45 km/ hr

We multiplied with 18/5 because:

1 m/s = 10⁻³ km / (1/3600) hr

        = 3600 / 1000 km /hr

        = 18/5 km/hr

Hope It Helps You!

Answer 2

$\underline{\underline{\bold{Question:}}}$

A car travels a distance of 15 km in 20 minutes.Find the speed of the car in (i) km h⁻¹    (ii) m s⁻¹.

$\underline{\bold{Solution:}}$

Given :

• The distance covered by the car = 15 km.
• Time taken by the car = 20 min = $\bold{\frac{20}{60}\:hr=\frac{1}{3}\:hr.}$

$\bold{\textsf{Let the speed of the car be x km per hr.}}$

$\boxed{\bold{Distance=Speed{\times}Time}}$

$\implies{\bold{15=x{\times}\frac{1}{3}}}\\\\\\\implies{\bold{x=45\:km\:h^{-1}.}}$

• Speed of car = 45 km per hr.

                              $\bold{=45{\times}\frac{1000}{3600}=\frac{25}{2}\:m\:s^{-1}.}$

$\boxed{\bold{Speed\:of\:the\:car=45\:km\:per\:hr=\frac{25}{2}\:m\:per\:s}}$