Question

9. The odometer of a car reads 4000 km at the start
of a trip and 4600 km at the end of the trip. If the
trip took 10 h, calculate the average speed of the
car in a. km/h and b. m/s. (Ans. a. 60 km/h, b. 16.6 m/s]​

Answer 1

Answer :-

(a) Average speed in 'km/h' = 60 km/h

(b) Average speed in 'm/s' = 16.6 m/s

Explanation :-

We have :-

→ Initial distance = 4000 km

→ Final distance = 4600 km

→ Time taken = 10 h

______________________________

Total distance covered by the car :-

= Final distance - Initial distance

= (4600 - 4000) km

= 600 km

Now, we know that :-

Average speed = Total distance/Total time

⇒ Average speed = 600/10

⇒ Average speed = 60 km/h

______________________________

Now, let's calculate average speed of the car in m/s .

⇒ 1 km/h = 5/18 m/s

⇒ 60 km/h = 60 × 5/18

⇒ 300/18 m/s

⇒ 16.6 m/s

Answer 2

Answer:

Given :-

• The odometer of a car reads 4000 km at the start of a trip and 4600 km at the end of the trip. The trip took 10 hours.

To Find :-

• What is average speed of the car in km/h and m/s.

Formula Used :-

$\clubsuit$ Average Speed Formula :

$\mapsto \sf\boxed{\bold{\pink{Average\: Speed =\: \dfrac{Total\: distance\: covered}{Total\: time\: taken}}}}$

Solution :-

First, we have to find the total distance covered by the car :

$\implies \sf \bold{Total\: distance\: covered =\: Final\: Velocity - Initial\: Velocity}$

$\implies \sf Total\: distance\: covered =\: v - u$

Given :

• Final Velocity (v) = 4600 km
• Initial Velocity (u) = 4000 km

$\implies \sf Total\: distance\: covered =\: 4600\: km - 4000\: km$

$\implies \sf\bold{\purple{Total\: distance\: covered =\: 600\: km}}$

Now, we have to find the average speed in km/h :

Given :

• Total distance covered = 600 km
• Total time taken = 10 hours

According to the question by using the formula we get,

$\longrightarrow \sf Average\: Speed =\: \dfrac{60\cancel{0}}{1\cancel{0}}$

$\longrightarrow \sf Average\: Speed =\: \dfrac{60}{1}$

$\longrightarrow \sf \bold{\red{Average\: Speed =\: 60\: km/h}}$

$\therefore$ The average speed in km/h is 60 km/h.

Again, we have to find the average speed in m/s :

$\longrightarrow \sf Average\: Speed =\: 60\: km/h$

$\longrightarrow \sf Average\: Speed =\: 60 \times \dfrac{5}{18}\: m/s$

$\longrightarrow \sf Average\: Speed =\: \dfrac{600}{18}\: m/s$

$\longrightarrow \sf \bold{\red{Average\: Speed =\: 16.6\: m/s}}$

$\therefore$ The average speed in m/s is 16.6 m/s.