Question

calculate the relative velocity when two bodies are moving with speed 30kmph and 60kmph in opposite directions​

Answer 1

Answer:

When two bodies are moving in opposite directions, relative velocity between them is equal to sum of the velocity of bodies. But if the bodies are moving in same direction their relative velocity is equal to difference in velocity of the bodies.

Answer 2

Given :

Velocity of body 1 ($V_{1}$) = 30 Km/hr = 8.33 m/sec

Velocity of body 2 ($V_{2}$) = 60 Km/hr = 16.67 m/sec

To Find :

The relative velocity between the moving bodies

Solution :

Relative velocity is defined as the apparent velocity of a body with respect to another body that may be in motion.

Relative Velocity ($V_{12}$)   = $V_{1} - V_{2}$

                                      =  8.33 - (-16.67)

(as the two bodies moving oppositely, $V_{2}$ = -16.67m/sec)

                                     = 25 m/sec

∴  The relative velocity when the two bodies are moving with speed 30kmph and 60kmph in opposite directions​ is 25 m/sec or 90 Km/hr.