Motion in a Straight Line
Motion in a straight line refers to the movement of an object along a straight path. It is one-dimensional motion where the object's position is described by a single coordinate. The key definitions for this chapter include:
- Distance: The length of the path traveled by an object.
- Displacement: The change in position of an object in a particular direction.
- Speed: The rate at which an object covers distance.
- Velocity: The rate at which an object changes its position in a particular direction.

Motion in a Plane
Motion in a plane refers to the movement of an object in two dimensions. This type of motion involves both horizontal and vertical components. The key definitions for this chapter include:
- Projectile motion: The motion of an object projected into the air and moving under the influence of gravity.
- Circular motion: The motion of an object around a fixed point in a circular path.
- Centripetal acceleration: The acceleration directed towards the center of a circular path.
- Tangential acceleration: The acceleration along the tangent to the circular path.

Units and Dimensions
Units and dimensions are essential aspects of physics that help in quantifying physical quantities. The key definitions for this chapter include:
- Units: Standard quantities used to measure physical quantities, such as meters for distance and seconds for time.
- Dimensions: The fundamental properties of physical quantities, such as length, mass, and time.
- Dimensional analysis: A method to check the correctness of equations by analyzing the dimensions of the terms on both sides.
- SI units: The International System of Units, which is the most widely used system of units in physics.