Relative Motion in Two Dimensions

These concepts can be extended to two-dimensional spaces also. Given in the figure below, consider a particle P and reference frames S and S’. The position of the frame S’ as measured in S is rS’S, the position of the particle P as measured with respect to the frame S’ is given by rPS’ and the position of the particle P with respect to the frame of reference S is given by rPS,

Notice from the figure that, 

rPS  = rPS’ + rS’S

These vectors give us the formula for relative velocities too, differentiating the above equation, 

Intuitively speaking, the velocity of a particle with respect to S is equal to the velocity of S’ with respect to S plus the velocity of the particle with respect to S. 

Differentiating this equation again, the equation for the acceleration is given by, 

 The acceleration of a particle with respect to S is equal to the acceleration of S’ with respect to S plus the acceleration of the particle with respect to S. 

Also, Read

Relative Motion in Two Dimension

The motion of the bodies is not absolute or isolated. It is always described with respect to some reference. For example, the speed of a moving vehicle is measured with respect to the ground. The position is also measured with respect to a reference which is called the origin. A train moving has a velocity of 100 Km/h with respect to the ground, but if another train is moving at 150 km/h. The velocity of the first train will not be 100 km/h with respect to the person sitting on the second train. It is essential to study the relative motion of the objects. Let’s explore this concept in detail. 

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