Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Scalars and Vectors: Scalar quantities have only magnitude (e.g., distance, speed), while vector quantities have both magnitude and direction (e.g., displacement, velocity, acceleration). Motion in a plane involves two-dimensional vectors.
Definition of Motion in a Plane: It refers to motion in two dimensions, where the position of an object is defined by two coordinates, typically . Examples include an object moving in a circular path or a projectile.
Uniform Circular Motion: When an object moves in a circular path with a constant speed, its motion is called Uniform Circular Motion. Although the speed is constant, the velocity is variable because the direction of motion changes continuously at every point.
Acceleration in Circular Motion: Since the velocity vector changes direction at every point along the circular path, circular motion is always an accelerated motion. The acceleration is directed towards the center of the circle.
Direction of Velocity: At any point on the circular path, the direction of the velocity vector is along the tangent to the circle at that point.
Centripetal Force: For an object to move in a circle, a force must act upon it towards the center of the path. This center-seeking force is called centripetal force.
📐Formulae
💡Examples
Problem 1:
An artificial satellite is moving in a circular orbit of radius . Calculate its speed if it takes to revolve around the earth.
Solution:
Given radius and time . Speed is calculated as: To convert to :
Explanation:
Since the satellite moves in a circular path, we use the circumference of the orbit as the distance covered in one revolution.
Problem 2:
A cyclist goes around a circular track once every . If the radius of the track is , calculate his speed. (Take )
Solution:
Radius , Time . Speed is:
Explanation:
The speed is found by dividing the total distance of one lap (circumference) by the time taken to complete that lap.