ROTATIONAL MOTION: At What Rate will the Yo-Yo Accelerate?

Several forces must be taken into account to study the motion of a yo-yo. If we assume a hand to be stationary when a yo-yo begins its descent, a tension force acts upward upon the yo-yo’s string. Opposite to the tension force is the force exerted upon the system by the gravitational force of attractionContinue reading “ROTATIONAL MOTION: At What Rate will the Yo-Yo Accelerate?”

ENERGY AND MOMENTUM: Parallel Axis Theorem/Moment of Inertia of a Rod

The moment of inertia ( I ) is the rotational equivalent of mass possessed by an object. This proclamation, however, comes with a caveat: massive objects are not created equal. Different objects of equal mass have differing abilities to resist changes in rotational motion. Additionally, the location of an object’s axis of rotation influences itsContinue reading “ENERGY AND MOMENTUM: Parallel Axis Theorem/Moment of Inertia of a Rod”

ROTATIONAL MOTION: What Distance Separates Two Projectiles Revolving Around a Common Center of Mass?

Q: Two projectiles separated by distance ( dt ) revolve around their center of mass ( cm = ½ dt ). Each projectile has a mass ( m ) of 4.81 x 1020 kg, and they have an instantaneous rotational speed ( ⍵ ) of 1.25 x 10-10 rad/s relative to the center of mass.Continue reading “ROTATIONAL MOTION: What Distance Separates Two Projectiles Revolving Around a Common Center of Mass?”

ROTATIONAL MOTION: Rotational Inertia

Q: A student sits atop a freely rotating stool holding two dumbbells, each of which has a mass of 3.09 kg. When the student’s arms are extended horizontally outward, the dumbbells are 0.99 m from the axis of rotation. There are 180 degrees of separation between the extended arms. The student rotates with an angularContinue reading “ROTATIONAL MOTION: Rotational Inertia”

CENTRIPETAL ACCELERATION

Q: What is the centripetal acceleration of a point located 7.50 cm from the central axis of an ultracentrifuge spinning at a rate of 7.5 x 104 rev/min? A: The given rate of 7.5 x 104 revolutions per minute is converted to radians per second ( ⍵ ) in the latter stages of the solutionContinue reading “CENTRIPETAL ACCELERATION”

OSCILLATIONS AND WAVES: The Period of a Pendulum

Q: A pendulum has a length of 2.45 m. How many seconds will it take the pendulum to swing through one complete cycle? Does the mass of the pendulum influence the period? Why or why not? A: This question regards the period ( T ) of a pendulum. The period ( T ) is definedContinue reading “OSCILLATIONS AND WAVES: The Period of a Pendulum”

RADIANT ENERGY: Wavenumber, Angular Frequency, and the Wave Nature of Light

Trigonometric functions such as sin ( θ ) and cos ( θ ) are commonly used to model the oscillating motion of traveling waves. In the diagram above, a complete wave cycle occurs from crest-to-crest, trough-to-trough, or along the x-axis as indicated by the blue line. Since the diagram above can be modeled with theContinue reading “RADIANT ENERGY: Wavenumber, Angular Frequency, and the Wave Nature of Light”