Question

The distance travelled by a car in 30 minutes is 18 km. Find its speed in km/h and convert the result to m/s.​

Answer 1

Answer:

9 km/h or 2.5 m/s

Explanation:

As per the provided information in the given question, we have :

• Time taken (t) = 30 minutes
• Distance covered (s) = 18 km

We've been asked to calculate its speed in km/h and then we have to convert the result to m/s.

Firstly, we'll calculate the speed in km/h. In order to do that so, we need to convert minutes into hours first.

$\longrightarrow \sf{\quad {t = 30 \; minutes }}$

• 1 minute = 1/60 hour

$\longrightarrow \sf{\quad {t =\cancel{ \dfrac{30}{60}} \; h }}$

$\longrightarrow \quad\underline{\boxed { \sf t = \dfrac{1}{2} \; h }}$

Now, as we know that,

$\bigstar \quad\underline{\boxed { \pmb{\frak{Speed = Distance \times Time}} }}$

$\longrightarrow \sf{\quad { Speed = \Bigg \lgroup \cancel{ 18} \times \dfrac{1}{\cancel{2}} \Bigg \rgroup \; km \: h^{-1} }}$

$\longrightarrow \sf{\quad { Speed = \Bigg \lgroup 9 \times 1 \Bigg \rgroup \; km \: h^{-1} }}$

$\longrightarrow \quad\underline{\boxed { \pmb{\frak{Speed = 9 \; km}} \: \pmb{\frak{h}}^{\pmb{\frak{-1}}} }}$

Therefore, speed in km/h is 9 km/h.

Now, we have to convert km/h into m/s. As we know that,

$\bigstar \quad\underline{\boxed { \pmb{\frak{1 \; km}}\: \pmb{\frak{h}}^{\pmb{\frak{-1}}} = \dfrac{\pmb{\frak{5}}}{\pmb{\frak{18}}} \; \pmb{\frak{m}} \: \pmb{\frak{s}}^{\pmb{\frak{1}} }}}$

$\longrightarrow \sf{\quad { Speed = \Bigg \lgroup \dfrac{5}{\cancel{18}} \times \cancel{9} \Bigg \rgroup \; m \: s^{-1}}}$

$\longrightarrow \sf{\quad { Speed = \Bigg \lgroup \dfrac{5}{2} \Bigg \rgroup \; m \: s^{-1}}}$

$\longrightarrow \quad\underline{\boxed { \pmb{\frak{Speed =2.5 \; m}} \: \pmb{\frak{s}}^{\pmb{\frak{-1}}} }}$

Therefore, speed in m/s is 2.5 m/s.