MYP Physics Speed, Motion Graphs Notes

How Do Motion Graphs Help Us Recognise Patterns In Movement?

1. When you watch a juggler, you cannot track every ball, but your brain still predicts where the balls will be.
2. Physics turns that intuition into measurable quantities and graphs so that motion can be described precisely and predictions can be tested.
3. Motion occurs when an object changes its position over time relative to a chosen reference point.

Quantities Used to Describe Motion

1. To describe motion accurately, physicists use several related quantities:
   1. Distance
   2. Displacement
   3. Time
   4. Speed
   5. Velocity
   6. Acceleration
2. Each quantity provides different information about how an object moves.

Scalars and Vectors

1. A scalar quantity has magnitude only
2. A vector quantity has both magnitude and direction.

Distance vs Displacement

Distance

1. Distance describes how much ground an object covers during its motion, regardless of where it starts or finishes.
2. It increases as an object keeps moving, even if the object changes direction.
3. Taking a longer or winding path results in a greater distance than taking a short or direct path.
4. Distance does not tell us anything about direction, only about the total movement.

Displacement

1. Displacement focuses only on the starting and finishing points, not on the path between them.
2. It shows how far an object has moved and in which direction.
3. An object can travel a long distance but still have a small or even zero displacement.
4. Displacement includes direction and can be positive, negative, or zero.

Speed And Velocity Tell How Fast Position Changes

To discuss "how fast," you need to decide whether direction matters.

Speed

1. Speed describes how fast an object is moving.
2. Speed does not include information about direction.