Glossary
Centrifugal Force
Centrifugal force is an apparent, fictitious force that seems to push an object away from the center of a rotating frame of reference, but it is not a real force.
Example:
When you're in a car turning sharply, you feel pushed outwards, which is the sensation of centrifugal force, though it's actually your inertia trying to continue in a straight line.
Centripetal Acceleration
Centripetal acceleration is the acceleration an object experiences when moving in a circular path, always directed towards the center of the circle.
Example:
Even though a car is moving at a constant speed around a curve, it still has centripetal acceleration because its direction of motion is constantly changing.
Centripetal Force
Centripetal force is the net force that acts on an object moving in a circular path, directed towards the center of the circle, causing the object to continuously change direction.
Example:
When a child spins on a merry-go-round, the force exerted by the seat on the child, pulling them inward, is the centripetal force.
Friction
Friction is a force that opposes motion or attempted motion between surfaces in contact.
Example:
The friction between a car's tires and the road allows it to make a turn without skidding, acting as the centripetal force.
Gravity
Gravity is a fundamental force of attraction between any two objects with mass.
Example:
The Earth's gravity provides the centripetal force that keeps the Moon in its orbit.
Mass (in UCM)
Mass is a measure of an object's inertia, or its resistance to changes in motion, and is a key factor in calculating centripetal force.
Example:
A heavier car (larger mass) requires a greater centripetal force to navigate the same turn at the same speed compared to a lighter car.
Normal Force
The normal force is the component of a contact force perpendicular to the surface that an object rests on or is in contact with.
Example:
When a roller coaster goes through a vertical loop, the track exerts a normal force on the car, which contributes to the centripetal force.
Radius (in UCM)
The radius in uniform circular motion is the constant distance from the center of the circular path to the object.
Example:
For a planet orbiting a star, the average distance from the planet to the star defines the radius of its nearly circular orbit.
Speed (in UCM)
Speed in uniform circular motion is the constant magnitude of the object's velocity as it moves along the circular path.
Example:
A fan blade spinning at a constant rate has a constant speed at any point on its edge, even though its velocity is continuously changing direction.
Tension
Tension is a pulling force transmitted axially by means of a string, cable, chain, or similar one-dimensional continuous object.
Example:
When you swing a ball on a string in a circle, the force exerted by the string on the ball is tension, providing the necessary centripetal force.
Uniform Circular Motion (UCM)
Uniform circular motion describes the movement of an object in a circular path at a constant speed.
Example:
A satellite orbiting Earth at a steady altitude and constant orbital speed is undergoing Uniform Circular Motion.
Vector Field
A vector field is a mathematical construct that assigns a vector (with both magnitude and direction) to each point in space.
Example:
An electric field around a charged particle is a vector field, showing the direction and strength of the force a positive test charge would experience at any point.
Velocity (in UCM)
In uniform circular motion, velocity refers to the instantaneous speed and direction of an object, which is always tangent to the circular path.
Example:
As a hammer thrower spins, the velocity of the hammer is always tangent to the circle, meaning if released, it would fly off in a straight line.