Question

a car covers fist half of the distance between two places at a speed 40 km/h and the second half at 60 km/h . the average speed of caris​

Answer 1

Given :

▪ A car covers first half of the total distance at a speed of 40kmph and second half of the total distance at a speed of 60kmph.

To Find :

▪ Average speed of car during the entire journey.

Concept :

↗ Average speed is 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

✴ If body covers first half of the total distance at a speed of V1 and second half of the total distance at a speed of V2, then average speed of body is given by

$\bigstar\:\underline{\boxed{\bf{\red{V_{av}=\dfrac{2V_1V_2}{V_1+V_2}}}}}$

Calculation :

$\dashrightarrow\sf\:V_{av}=\dfrac{2V_1V_2}{V_1+V_2}\\ \\ \dashrightarrow\sf\:V_{av}=\dfrac{2\times 40\times 60}{40+60}\\ \\ \dashrightarrow\sf\:V_{av}=\dfrac{4800}{100}\\ \\ \dashrightarrow\underline{\boxed{\bf{\orange{V_{av}=48kmph}}}}\:\blue{\bigstar}$

Learn More :

☣ If a particle moves in two equal intervals of time at different speed V1 and V2 respectively, then

$\bigstar\:\underline{\boxed{\bf{\green{V_{av}=\dfrac{V_1+V_2}{2}}}}}$

☣ When particle covers one-third distance at speed V1, next one-third at speed V2 and last one-third at speed V3, then

$\bigstar\:\underline{\boxed{\bf{\purple{V_{av}=\dfrac{3V_1V_2V_3}{V_1V_2+V_2V_3+V_1V_3}}}}}$