9TH GRADE · KINEMATICS
Frame of reference and uniform motion
Material point, coordinate, displacement, projections and graphs.
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
Material point
A model of a body whose size and shape can be neglected when solving the selected problem.
A car can be considered a point on a long highway, but not when analyzing its parking in a cramped garage.
Translation and projection
The displacement is a vector from the initial position to the final position, and the projection defines its component on the axis.
Projection can be positive, negative or zero; the path remains a non-negative trajectory length.
Coordinate equation
The dependence of the coordinate on time allows you to predict the position and build a motion graph.
For a constant velocity projection, the coordinate graph is straight, and its slope is equal to the velocity projection.
Physical quantities
Coordinate
The position of a material point on the selected coordinate axis.
Unit: meter ·
Motion projection
Change in body coordinates over the period under consideration.
Unit: meter ·
Projection of speed
Change in coordinate per unit time with uniform motion.
Unit: meter per second ·
Time
The duration of the movement in question.
Unit: second ·
Lesson formulas
Uniform motion coordinate
The coordinate is equal to the initial coordinate plus the product of the velocity projection and time.
Moving uniform motion
The projection of displacement is equal to the product of the constant projection of velocity and time.
Related formulas
The same formulas in the reference, with symbols and units.
Tasks on the topic
Statements, answer options and the walkthrough.