When solving physics problems, understanding and selecting the correct reference frames can make a big difference. A reference frame is essentially a perspective from which you measure velocity and position. By choosing different reference frames, the observed velocity of objects can change, which influences how we analyze motion.
- A reference frame could be stationary, like the ground.
- It could also be another moving object, like a car traveling down a highway.
In the context of the problem, if you're standing on object 2, you see object 1 move at \(v_{12}\). But if you switch to standing on object 3, you need to account for object 2's motion relative to object 3 as well. This is why reference frames are crucial; they dictate how velocities are perceived and how we apply the velocity addition rule properly.