Q: Two acrobats, a pulley, and a rope are used in a circus act. Acrobat 1 rapidly climbs one of the suspended lengths of rope at a distance of 16ft in 2 seconds with a constant acceleration. On the opposite length of rope, acrobat 2 is suspended in an attached chair that remains motionless aboveContinue reading “FORCE AND ACCELERATION: What is the mass of the climbing acrobat?”
Author Archives: George Tafari
FORCE AND ACCELERATION: The Sum of all Torques Must Equal Zero
When a system is in static equilibrium, the sum of the forces acting upon the system must equal zero. In the diagram below, forces F1 and F2 exert torques upon the system: Recall that a torque ( 𝛕 = Fr sin θ ) has the ability to make a system rotate, and it is theContinue reading “FORCE AND ACCELERATION: The Sum of all Torques Must Equal Zero”
ENERGY AND MOMENTUM: Stacked Ball Drop, Impulse, and the Galilean Transformation
Q: Three balls of mass m1, m2, and m3 fall together towards the earth. They accelerate until impact, and once the three-ball system collides elastically with the earth’s surface, the balls within the system approach one another with an instantaneous velocity ( v ). The momentum ( p = mv ) = ( m1 +Continue reading “ENERGY AND MOMENTUM: Stacked Ball Drop, Impulse, and the Galilean Transformation”
FORCE AND ACCELERATION: Relative Velocity of Satellites in Orbit
Q: A satellite circles a planet with a tangential velocity of 1.70 x 104 m/s. The orbital radius ( r1 ) is 5.25 x 106 m. A second satellite of equal mass revolves around the same planet with an orbital radius ( r2 ) of 8.60 x 106 m. What is the orbital speed ofContinue reading “FORCE AND ACCELERATION: Relative Velocity of Satellites in Orbit”
FORCE AND ACCELERATION: Pulleys, Tension, Friction, and Free-Body Diagrams
Q: Three objects are connected by ropes that pass over massless and frictionless pulleys. As the objects move, the table exerts a force of friction on the middle object. The coefficient of kinetic friction is 0.100. What is the acceleration of the three objects within the system? What is the magnitude of the tension inContinue reading “FORCE AND ACCELERATION: Pulleys, Tension, Friction, and Free-Body Diagrams”
FORCE AND ACCELERATION: Mechanical Advantage and Tension Within Pulley Systems
The law of conservation of energy states that the total energy of an isolated system remains constant. The SI unit of energy is the joule ( J ), and it’s base-unit composition is kg*m2/s2. Energy is the currency needed to perform work, and work is performed upon an object when an applied force moves itContinue reading “FORCE AND ACCELERATION: Mechanical Advantage and Tension Within Pulley Systems”
FORCE AND ACCELERATION: Systems of Torque and the Center of Mass
Thus far, physicists have not developed a concise definition of what constitutes mass and “ free space “. As a consequence, an overly simplistic definition of mass, albeit imperfect, may be used with convenience in laboratory settings. Mass, simply put, occupies free space. Relatively simple analyses of forces acting upon massive objects can be madeContinue reading “FORCE AND ACCELERATION: Systems of Torque and the Center of Mass”
GEOMETRICAL OPTICS: Thin Convex Lenses
Spherical wavefronts of radiation emanate from point sources of light. As the electromagnetic wavefront expands, it carries energy and momentum that become more dispersed as the wavefront gets larger. If the distance between a light source and detector ( such as the human eye ) is infinite, the light detector will intercept a small componentContinue reading “GEOMETRICAL OPTICS: Thin Convex Lenses”
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”
KINEMATICS: Free Fall Dynamics
Q: An Olympic high diving platform is situated 10 m above the surface of a pool. If a diver steps off the platform, how long does it take for her to hit the water? A: The only information provided is the 10 m distance between the diving platform and the pool’s surface. This necessitates useContinue reading “KINEMATICS: Free Fall Dynamics”
RENAISSANCE PHYSICS 