Correct Answer - Option 3 : 0
Correct option - 3
Concept:
Relative velocity
- The velocity of a moving object with respect to another object either moving or in rest is termed as Relative motion.
- The term relative is actually applied to physical, non-physical, scalar, or vector quantities. In fact, all the measurements are relative to physics.
- In relative motion, questions are not so complicated as the objects moving with uniform velocities and It is very important to understand many day-to-day events based on it like- Rain man, Boatman problems, the velocity of approach, the velocity of separation, etc.
- In this topic, we will consider the velocity with respect to the frame of reference attached to the ground.
For example-
Let us consider two objects, X and Y are moving with velocities V1 and V2 with respect to a common stationary frame of reference, say the ground, a tree or a fixed platform.
The velocity of the object X relative to the object Y can be given as,
V12 = V1 - V2
Similarly, the velocity of the object Y relative to that of object X is given by,
V21 = V2 - V1
From the above two expressions, we can see that
V12 = -V21
Although the magnitude of both the relative velocities is equal to each other.
Mathematically, it is written as-
|V12| = |V21|
Explanation:-
When two balls are thrown vertically,
They both have the same acceleration due to gravity (g).
So, the relative acceleration of ball one with respect to another ball is given by :-
arel = a1 - a2
arel = -g - (-g) = 0
arel = 0
Hence, option - 3 is the correct answer.
The relative velocity concept is used to calculate the velocities of stars and asteroids with respect to the earth’s velocity.
The distance between any two things in space can be calculated by the concept of relative velocity.
Some of the engineering applications of relative velocity are
- Mid-air fueling of fighter jets
- Launching rockets.
- Speed Detectors.
