Question

The Odometer of a car reads 5000 km at the start of the trip and 5600 km at the end of the trip. If the trip took 5hrs. Calculate average speed of the car in km/h and m/s

Answer 1

Given :

▪ Initial reading = 5000km

▪ Final reading = 5600km

▪ Time of journey = 5hrs

To Find :

▪ Average speed of car in

• km/h
• m/s

Concept :

☞ Average speed ia defined as the ratio of total distance travelled to the total time taken.

☞ It is a scalar quantity.

☞ It has only magnitude.

☞ It can't be negative or zero.

☞ SI unit : m/s

Calculation :

Distance travelled

= 5600 - 5000

= 600km

✴ Average speed in km/h :

→ Vav = d/t

→ Vav = 600/5

→ Vav = 120kmph

✴ Average speed in m/s :

→ 1km/h = 1000/3600 = 5/18m/s

→ 120km/h = 120×5/18

→ Vav = 33.33mps

Answer 2

Given that ,

• Total distance = 600 km or 600000 m

• Time = 5 hr or 18000 sec

We know that ,

The ratio of total distance to the total time is called average speed

The SI unit of average speed is m/s

Average speed is scalar quantity

Thus ,

The average speed in terms of km/hr will be

Average speed = 600/5

Average speed = 120 km/hr

Now ,

The average speed in terms of m/s will be

Average speed = (600000)/18000

Average speed = 33.3 m/s

$\therefore \sf \underline{The \: average \: speed \: of \: the \: car \: is \: 120 \: km \: or \: 33.3\: m/s}$