Question

14P. A travels from A to B with a
velocity 36km/hr and returns to A
with 72km/hr. What are the average
speed and the average velocity?​

Answer 1

Given :

Velocity from A to B = 36km/h

Velocity from B to A = 72km/h

To find :

(a) The average speed

(b) The average velocity

Solution :

(a) Average speed is the ratio of total distance travelled to the total time taken.

• It is scalar quantity having magnitude
• SI unit is metre per second
• CGS unit is cm/s.

According to Question,

A body is traveling between two positions A and B. It travels from A to B will speed v₁ and then from B to A in the same path with speed v₂ the average speed is given as,

$\sf Average \: Speed = \dfrac{2v_1v_2}{v_1 + v_2}$

$\sf Average \: Speed = \dfrac{2 \times 36 \times 72}{36 + 72}$

$\sf Average \: Speed = \dfrac{5184}{108}$

$\sf Average \: Speed = 48 \: km/h$

thus, the Average speed is 48 km/hr

(b) In this case displacement is zero as the average velocity = 0/∆t = 0