Question

Rajeev went from Delhi to Chandigarh on his motorbike. The odometer of the bike read 4200 km at the start of trip and 4460 km at the end of his trip. If Rajeev took 4 h 20 minutes to complete his trip, find the average speed in km/has well as in m/s

Answer 1

 Here, u=4200km, v=4460 km t=4h 20 min, t= 4h+1/3hr=13/3hr

Therefore, Average speed = distance/time d=4460-4200=260km t= 13/3 hr

That implies, 260/13/3=260/13*3=20*3 = 60kmph Now, 1kmph=5/18 m/s

Therefore, 60kmph=60*5/18=16.66 m/s

Answer 2

Answer: the average speed of the motorbike in m/s is 16.66m/s.

Explanation:

At the start of this trip, the odometer reading was, 4200km.

At the end of the trip, the odometer reading is, 4460km.

The total distance traveled by the motorbike is ΔS=4460−4200=260km

The total time taken to cover the distance is 4h 20min

Now, the conversion of the time from minute to hour is given by dividing the minute value by 60.

Hence, the minute value is:

$\frac{20}{60} =\frac{1}{3}h$

Therefore, the total time taken in hours is,

$4\frac{1}{3} =\frac{13}{3}h$

Now, using the average speed formula, we can find the value of speed in terms of km/h as; $v _{avg} = \frac{st}{t}$

Placing the value of distance and time in the above formula, we get the value of the average speed as:

$v_{avg} = \frac{260}{(\frac{13}{3} )}$

⇒ $v_{avg} = \frac{260 \times 3}{13} = 60km/h$

We are asked to calculate the motorbike’s average speed in m/s.

To convert kilometres to meters, we need to multiply the value in kilometres by 1000.

We also know that an hour is 60 minutes and 60 minutes is 60×60=3600s.

Hence, to convert the hour to the second, we need to multiply the value in the hour by 3600.

Therefore, to convert km/h to m/s we need to multiply 60km/h by $\frac{1000}{3600}$.

i.e. 60km/h = $60 \times \frac{1000}{3600}$m/s

⇒ 16.66m/s

Hence, the average speed of the motorbike in m/s is 16.66m/s.

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