Question

A train, travelling at uniform speed takes 10 hours to cover a distance of 1200 km. Express its speed in

km/h and m/s.​

Answer 1

Answer:

Given:

Time = 10 hour

Distance = 1200 km

To find:

The speed of the train in km/h.

The speed of the train in m/s.

Solution:

Time = 10 hour.

Distance = 1200 km.

We know that,

Speed = \dfrac{Distance}{Time}Speed=TimeDistance

=\dfrac{1200}{10}=101200

= 120 km/h

∴ The speed of the train is 120 km/h.

The speed of the train in m/s _

120×(5/18)

= (120×5)/18

= (20×5)/3

= 100/3

=33\dfrac{1}{3} m/s=3331m/s

∴ The speed of the train is 33\frac{1}{3}3331m/s.

Answer:

          The speed of the train is 120 km/h.

          The speed of the train is 33\frac{1}{3} m/s3331m/s

Answer 2

Required Answer :

Given:

• Time taken by the train (t) = 10 hrs

• Distance covered (s) = 1200 km

To calculate :

• Speed of the train in km/h and m/s

Calculation:

In km/h :-

We know that,

★ $\boxed {\sf{Speed(v) = \dfrac{Distance (s)}{time(t)}}}$

$\sf { \longrightarrow v = \dfrac{1200 \: km}{10 \: hr}}$

$\sf \red{ \longrightarrow v = 120 \: km/h }$

Therefore, speed of the train is 120 km/h.

______________________.....

In m/s :-

We know that,

★ $\boxed {\sf{Speed(v) = \dfrac{Distance (s)}{time(t)}}}$

Before substitution, let us first convert the given physical quantities into its standard form:

• → Distance = 1200 km = 12,00,000 m

→ 1 km = 1000 m

→ 1200 km = (1000 × 1200)m

→ 1200 km = 12,00,000 m

• → Time = 10 hrs = 36000 seconds

→ 1 hr = 60 minutes

→ 10 hrs = (10 × 60) minutes

→ 10 hrs = 600 minutes

◆ 1 minute = 60 seconds

→ 600 minutes = ( 60 × 600 ) seconds

→ 600 minutes = 36,000 seconds

Now, let's substitute the values in the formula :

★ $\boxed {\sf{Speed(v) = \dfrac{Distance (s)}{time(t)}}}$

$\sf { \longrightarrow v = \dfrac{12,00,000 \: m}{36,000 \: s}}$

$\sf { \longrightarrow v = \dfrac{1200 \: m}{36 \: s}}$

[ Cancelling the denominator and numerator by 6. ]

$\sf { \longrightarrow v = \dfrac{100 \: m}{3 \: s}}$

[ Cancelling the denominator and numerator by 2. ]

$\sf \red { \longrightarrow v = 3.33 \: m/s }$

_________....

[Note : Also, we can convert the km/h into m/s by multiplying it by 5/18. ]

In the first part of the question we got that the speed is 120 km/h.So, to express the speed into m/s, we will multiply 120 km/h by 5/18.

$\sf { \longrightarrow \dfrac{5}{18} \times 120}$

$\sf { \longrightarrow \dfrac{5 \times 120}{18} }$

$\sf { \longrightarrow \dfrac{600}{18} }$

$\sf { \longrightarrow \dfrac{100}{3} }$

$\sf \red { \longrightarrow v = 3.33 \: m/s }$

So, we can solve this part of the question by two methods.

Therefore, final answer :

• Speed ( in km/h ) = 120 km/h

• Speed ( in m/s ) = 3.33 m/s