Question

1. describe some types of motion we can and cannot observe.

2.1

1. what does it mean to say that motion is relative?
2. how fast is your book moving with respect to the desk? what about relative to the sun?

2.2

1. what is speed?

Explanation:

1. For observable motion: These are movements we can directly see or detect with basic senses. Unobservable motion is too small, slow, or fast for human perception without tools.
2. Motion being relative means an object's movement is only defined compared to another chosen reference point.
3. The book's speed depends entirely on the reference frame; the desk is a stationary local frame, while the sun is a moving cosmic frame.
4. Speed is a core kinematic quantity that measures how quickly an object covers distance.

Answer:

1. Observable motion examples:

• Translational motion: A car driving down a road, a person walking.
• Rotational motion: A spinning ceiling fan, a turning bicycle wheel.

Unobservable motion examples:

• Atomic/subatomic motion: Vibrations of atoms in a solid, movement of electrons around an atomic nucleus.
• Very slow motion: Continental drift (tectonic plates moving a few centimeters per year).

1. It means that an object's state of motion (moving or stationary) can only be defined by comparing it to a chosen reference point; there is no absolute "stationary" frame of reference.
2. Relative to the desk: The book has a speed of 0 m/s (it is stationary if resting on the desk).

Relative to the sun: The book moves at ~30 km/s, matching Earth's orbital speed around the sun.

1. Speed is a scalar quantity that measures the rate at which an object covers a distance, calculated as the distance traveled divided by the time taken.