Comprehensive notes for Chapter 2 Force and Motion. Covers Vectors, Equations of Motion, Projectile Motion, Momentum, Collisions, and Rocket Propulsion.
Scalar Quantities: Physical quantities described completely by their magnitude only (e.g., Mass, Distance, Speed, Energy).
Vector Quantities: Physical quantities described by both magnitude and direction (e.g., Displacement, Velocity, Force, Torque).
Scalar (Dot) Product: The product of two vectors resulting in a scalar quantity.
Formula: A . B = AB cos θ.
Examples: Work (F.d), Power (F.v).
Vector (Cross) Product: The product of two vectors resulting in a vector quantity perpendicular to the plane of the two vectors.
Formula: A x B = AB sin θ n̂.
Examples: Torque (r x F), Magnetic Force (q v x B).
These equations apply to objects moving with uniform acceleration in a straight line:
For motion under gravity, replace 'a' with 'g' (9.8 ms-2).
Linear Momentum (p): The product of mass and velocity (p = mv). It is a vector quantity.
Impulse (J): The product of a large force acting for a short time (J = F x Δt). It equals the change in momentum (Δp).
Newton's Second Law (in terms of momentum): The rate of change of momentum is equal to the applied force (F = Δp/Δt).
Elastic Collision: A collision where both Kinetic Energy (K.E) and Momentum are conserved (e.g., collision between gas molecules).
Inelastic Collision: A collision where Momentum is conserved, but Kinetic Energy is NOT conserved (e.g., car crash).
2D motion under constant acceleration due to gravity. Horizontal velocity remains constant; vertical velocity changes.
works on the Law of Conservation of Momentum and Newton's Third Law. The rocket ejects burnt gases backward at high speed, gaining forward momentum.
Acceleration: a = Mgasv / Mrocket. Acceleration increases as fuel is consumed because the mass of the rocket decreases.