OCR A Physics A-level Topic 5.3: Circular Motion

The angle subtended at the center of a circle by an arc equal in length to the radius of the circle.

The time it takes for an object to complete one full revolution in a circular path.

The rate at which an object changes its angular position.

The rate of change of velocity.

The force that acts perpendicular to the velocity of an object, always directed towards the center of the circular path. It is responsible for changing the direction of the object's velocity, causing it to move in a circle.

The acceleration that an object experiences due to the centripetal force. It is always directed towards the center of the circular path.

The relationship between the period (T) and the angular velocity (ω).

The relationship between the speed (v) of an object moving in a circle and its angular velocity (ω) and radius (r).

The formula to calculate the centripetal force (F) required to keep an object moving in a circle, where m is the mass, v is the speed, and r is the radius.

The conversion formula to convert an angle measured in degrees to radians.

The frequency of an object moving in a circular path is the number of complete revolutions it makes per second.

The relationship between frequency (f) and period (T).

The technique involves attaching a bung (the object) to a string, threading the string through a glass tube, and attaching a weight to the other end of the string. By rotating the tube, the bung moves in a circle, with the weight providing the centripetal force.

The force provided by the weight attached to the string in the experimental technique. This force is directed towards the center of the circular path, keeping the bung moving in a circle.

The object that moves in a circular path in the experimental technique.

The role of the glass tube in the experimental technique is to provide a smooth surface for the string to move through, ensuring that the force of gravity acts downwards.

The source of the centripetal force in the circular motion experiment.

The unit of measurement for angular velocity, derived from the ratio of arc length to radius.

The angle subtended at the center of a circle by an arc equal in length to the circumference of the circle.

The direction of the net force acting on an object moving in a circular path is always towards the center of the circle.

The relationship between the speed of an object moving in a circle and its angular velocity. Speed is proportional to angular velocity and radius.

The centripetal force required to maintain an object's circular motion is directly proportional to its mass.

If the radius of the circular path increases while the speed remains constant, the centripetal force needed to maintain circular motion decreases.

The centripetal force cannot be zero for an object moving in a circular path. A non-zero force is required to change the object's direction and keep it moving in a circle.

The bung is the object moving in a circular path in the experimental technique to investigate circular motion.

The acceleration of an object moving in a circular path is the rate of change of its velocity. The centripetal acceleration is responsible for changing the direction of the object's velocity, keeping it moving in a circle.

The glass tube in the experimental technique keeps the string vertical, ensuring that the force of gravity acts downwards.

When calculating the centripetal force, it's important to consider the resultant force because multiple forces may be acting on the object. The centripetal force is the net force acting towards the center of the circle.

Radians are a more natural and fundamental unit for measuring angles in circular motion than degrees. They are directly related to the radius of the circle, making calculations simpler.

If the period of an object moving in a circle is halved, its angular velocity doubles.

The direction of the centripetal force is crucial for maintaining circular motion. It is directed towards the center of the circle, responsible for changing the object's direction of motion.

The frequency is the number of complete cycles or revolutions completed in one second. It's directly related to the period, with the frequency being the reciprocal of the period.

The angular velocity of an object moving in a circle is constant, even though its velocity is changing because the rate of change of angle is consistent. Even though the direction of velocity is changing, the angular velocity describes the consistent rate of change of the angle.

The radius is integral in defining the radian, the unit of measurement for angular velocity. The bigger the radius, the larger the angle subtended by a given arc length.

The centripetal force is essential for maintaining circular motion because it provides the necessary acceleration towards the center of the circle. Without this force, an object would move in a straight line due to inertia.

The period of an object moving in a circle is the time it takes to complete one full revolution. It is measured in seconds.

Understanding angular velocity is crucial because it describes the rate of change of angle, a fundamental aspect of circular motion. It allows us to analyze and predict the behavior of objects moving in circular paths.

An object must be accelerating, which means its velocity is changing, for it to change its velocity. This acceleration is provided by the centripetal force.

The formula v = ωr relates the speed (v) of an object moving in a circle to its angular velocity (ω) and radius (r). This formula is essential for understanding the relationship between these quantities in circular motion.

The direction of the centripetal acceleration is always towards the center of the circle, which is consistent with the direction of the centripetal force.

The expression for the centripetal force in terms of mass (m), velocity (v), and radius (r) is F = m(v^2)/r. This formula is essential for calculating the force needed to maintain an object's circular motion.

The glass tube in the experimental technique provides a smooth surface for the string to move through, minimizing friction and allowing the bung to move in a circular path.

If the radius of the circle increases but the speed remains constant, the centripetal force required to maintain the circular motion decreases. This is because the force is inversely proportional to the radius.

Understanding resultant force is crucial in calculating centripetal force because it represents the net force acting on the object. Centripetal force is the net force acting towards the center of the circle, considering all forces acting on the object.

The relationship between angular velocity (ω) and the period (T) of an object moving in a circle is given by ω = 2π/T. This formula highlights that angular velocity is inversely proportional to the period.

Centripetal force plays a crucial role in circular motion by consistently providing the necessary acceleration towards the center of the circle. This acceleration is responsible for changing the object's direction of motion, allowing it to move in a circular path instead of continuing a straight line.

Angular velocity physically represents the rate of change of angle of an object moving in a circle. It quantifies how quickly the object's angular position changes over time.

The angular velocity (ω) of an object moving in a circle is inversely proportional to its period (T). This means that as the period increases (object takes longer to complete a revolution), the angular velocity decreases.

The velocity of an object moving in a circle is constantly changing in direction, even if its speed remains constant. Velocity is a vector quantity, taking both magnitude and direction into account.

Centripetal force is essential for an object to move in a circle because it provides the necessary acceleration towards the center of the circle. This acceleration is required to change the direction of the object's velocity, preventing it from moving in a straight line due to inertia.

Converting an angle from degrees to radians simplifies calculations involving angular velocity and frequency because radians are directly related to the radius and circumference of the circle, making calculations more natural and efficient.