Question

The odometer of a car reads 2000 km at the start of a trip and 2400 km at the end of the trip. If the trip took 8 hours, calculate the average speed of the car in km/hr and in m/sec.

Answer 1

Answer:

50km/hr and 13.889m/s

Explanation:

Initial distance: 2000km

Final distance: 2400km

Time taken: 8hrs

Total distance covered: 2400-2000

400km

km/hr = 400/8

50kmph

m/s = 50/1 × 5/18

13.889m/s

Answer 2

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✰Answer✰

♦️GiveN

• Initial reading of Odometer = 2000 km
• Final reading of Odometer = 2400km
• Time taken = 8 hours

♦️To FinD

• Average speed in km/hr and m/s

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✰We must know✰

➯AVERAGE SPEED

The average speed of the body in a given time interval is defined as the total distance travelled per unit time/ total time.

${ \boxed{ \rm{ \star{ \red{ \: average \: speed = \frac{total \: distance \: travelled}{total \: time \: taken} }}}}}$

➯Here, distance travelled will be final reading of Odometer - Initial reading and time taken given 8 hours.

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✰Solution✰

➯As the distance is in km and time taken in hrs, Average speed will be in km/hr.

$\rm{total \: distance = 2400 \: km - 2000 \: km} \\ \\ \rm{ total \: time = 8 \: hours}$

➯By using formula,

$\rm{ \rightarrow \: average \: speed(in \: km) = \frac{400 \: km}{8 \: hr} } \\ \\ { \rightarrow \: \boxed{ \purple{ \rm{ average \: speed(in \: km) = 50 \: km {h}^{ - 1} }}}}$

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➯Now, Little unit conversion is needed...

✰Converting into m/s

$\rm{1 \: km = 1000m} \\ \\ \rm{ \implies \: 400km = 400000m} \\ \\ \rm{ 1 \: hour = 3600 \: s(60 \times 60)} \\ \\ \rm{ \implies \: 8 \: hours = 3600 \times 8 \: s = 28800 \: s}$

➯By using formula,

$\rm{ \rightarrow \: average \: speed = \cancel{\frac{400000}{28800} m {s}^{ - 1} }} \\ \\ \rm{ \rightarrow \: average \: speed \: = \frac{125}{9} m {s}^{ - 1} } \\ \\ \rightarrow \: \boxed{ \purple{ \rm{average \: speed = 13. \bar{8} \: m {s}^{ -1 } }}}$

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