Question

The odometer of a car reads 2000km at the start of a trip and 2400km at the end of the trip if the trip 28hr calculate the average speed of the car in km/hr and m/s

Answer 1

━━━━━━━━━━━━━━━━━━━━

✺Answer:

♦️GiveN:

• Initial reading of Odometer = 2000 km
• Final reading of Odometer = 2400km
• Time taken = 28 hours

♦️To FinD:

• Average speed in km/hr and m/s

━━━━━━━━━━━━━━━━━━━━

✺We must know:

⏺AVERAGE SPEED

The average speed of the body is defined as the total distance travelled per unit time/ total time. We know that speed is rate of distance travelled, so average means the rate of total distance travelled.

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

♠️Here, distance travelled will be final reading of Odometer - Initial reading and time taken given 28 hours.

━━━━━━━━━━━━━━━━━━━━

✺Solution:

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

Total distance = 2400 km-2000 km = 400km

Total time = 28 hours

By using formula,

$\large{\rm{ \rightarrow average \: speed(in \: km) = \frac{400 \: km}{28 \: hr} }} \\ \\ \large{ \rightarrow \boxed{ \purple{ \rm{ average \: speed = 14.285 \: km {h}^{ - 1} }}}}$

━━━━━━━━━━━━━━━━━━━━

Now, Little unit conversion is needed...

♠️Converting into m/s

$\large{\rm{1 \: km = 1000m}} \\ \\ \large{\rm{ \rightarrow 400km = 400000m}} \\ \\ \large{\rm{ 1 \: hour = 3600 \: s(60 \times 60)}} \\ \\ \large{\rm{ \rightarrow 28 \: hours = 3600 \times 28 \: s = 100800 \: s}}$

By using formula,

$\large{ \rm{ \rightarrow average \: speed = \cancel{\frac{400000}{100800}} \: m {s}^{ - 1}}} \\ \\ \large{ \rm{ \rightarrow average \: speed = \frac{250}{63} \: m {s}^{ - 1}}} \\ \\ \large{ \rm{ \rightarrow \boxed{ \purple{ \rm{ average \: speed = 3.968 \: m {s}^{ - 1} }}}}}$

✒Hence, solved!

━━━━━━━━━━━━━━━━━━━━