Kinematics

Understanding motion, displacement, velocity, and acceleration

Topics

How do projectiles move?

Projectiles move in curved paths called parabolas due to the combination of horizontal motion (constant velocity) and vertical motion (constant acceleration downward due to gravity). The horizontal and vertical motions are independent, creating the characteristic curved trajectory.

How does gravity work?

Gravity is a fundamental force that attracts all objects with mass toward each other. The strength of gravity depends on the mass of the objects and the distance between them, following Newton's law of universal gravitation.

What is acceleration?

Acceleration is the rate at which an object's velocity changes over time. It describes how quickly an object speeds up, slows down, or changes direction.

What is displacement?

Displacement is the change in position of an object from its starting point to its ending point, measured in a straight line with direction. Unlike distance, displacement is a vector quantity that includes both magnitude and direction.

What is free fall?

Free fall is the motion of an object falling under the influence of gravity alone, with no other forces (like air resistance) acting on it. In free fall, all objects accelerate downward at the same rate, approximately 9.8 m/s² on Earth, regardless of their mass.

What is the difference between speed and velocity?

Speed is how fast an object is moving (a scalar quantity with only magnitude), while velocity is how fast an object is moving in a specific direction (a vector quantity with both magnitude and direction). The key difference is that velocity includes direction, while speed does not.

What is velocity?

Velocity is the rate at which an object changes its position, including both speed and direction. Unlike speed, velocity is a vector quantity that describes how fast something is moving and in which direction.

Why do objects fall?

Objects fall due to gravity, a fundamental force that pulls all objects with mass toward each other. On Earth, gravity pulls objects toward the center of the planet, causing them to fall downward.

Why do objects follow curved paths?

Objects follow curved paths when forces act perpendicular to their direction of motion, changing their direction continuously. Common causes include gravity (creating parabolic paths for projectiles), centripetal forces (creating circular paths), and the combination of multiple forces acting at angles to the motion.

Why do objects move?

Objects move because of forces acting on them. According to Newton's laws of motion, an object at rest stays at rest unless acted upon by a force, and an object in motion continues moving unless acted upon by a force.