Question

section 3: motion and forces continued
not all objects fall to the earth at the same time, and this is because of air resistance, which acts as a friction - like force opposing the motion of objects moving through air. when an object collides with the air, it experiences deceleration caused by the resistance of the air molecules. whether an object falls faster or slower depends on factors such as its speed, size, and shape. for instance, a flat sheet of paper will fall slower than a crumpled - up sheet of paper because the flat sheet of paper collides with more air particles.

1. what is a net force?
2. compare static friction to sliding friction
3. explain air - resistance

Explanation:

1. Net force is the vector sum of all forces acting on an object. It determines the object's acceleration according to Newton's second - law ($F_{net}=ma$).
2. Static friction acts on an object at rest to prevent it from starting to move. Sliding friction acts on a moving object and opposes its motion. Static friction is generally greater than sliding friction for the same two surfaces in contact.
3. Air - resistance is a friction - like force that opposes the motion of objects moving through air. It is caused by the collision of an object with air molecules. Factors like an object's speed, size, and shape affect the amount of air - resistance it experiences.

Answer:

1. The vector sum of all forces acting on an object.
2. Static friction prevents a stationary object from moving; sliding friction opposes the motion of a moving object. Static friction is usually greater than sliding friction for the same surfaces.
3. A friction - like force that opposes the motion of objects moving through air, caused by collisions with air molecules and affected by speed, size, and shape of the object.