7TH GRADE · MASS AND DENSITY
Inertia, interaction and mass
Why speed does not change instantly and how the masses of bodies are compared.
The entire theory of the lesson is collected here; you can read it without an account. In interactive mode, the same theory appears as cards, followed by questions. with checking the answer and task, and progress is saved.
Basic Concepts
Inertia
The phenomenon of maintaining the speed of a body when external influences are absent or mutually balanced.
The cart does not stop instantly on its own: its speed is changed by frictional forces and air resistance.
Interaction of bodies
When interacting, each body acts on the other and can change its speed or shape.
After the collision, both carts change motion, although the changes may be different due to the difference in mass.
Mass
A physical quantity that characterizes the inertia of the body and serves as a measure of the amount of substance at the school level.
The greater the mass of the cart, the more difficult it is to noticeably change its speed using the same influence; mass is measured with scales.
Physical quantities
Mass
A quantitative measure of the inertia of the body in question.
Unit: kilogram ·
Related formulas
The same formulas in the reference, with symbols and units.
Tasks on the topic
Statements, answer options and the walkthrough.