Q: Wind blows a 43.0 kg raft across a lake at 1.1 m/s northward relative to the water underneath. It carries a passenger whose mass is 38.0 kg. The passenger begins to walk westward at 0.71 m/s. What is the final velocity of the raft relative to the water? A: We first determine the momentumContinue reading “ENERGY AND MOMENTUM: A Windy Day at the Lake”
Category Archives: Energy and Momentum
ENERGY AND MOMENTUM: What is the final velocity of the hovering disk?
Q: A disk of mass 0.5 kg slides with a constant velocity of 2.4 m/s over an air table before colliding with an elastic band. If the band exerts an average force of 1.4 Newtons on the disk for 1.5 seconds, what is the final velocity of the disc? A1: The disc will experience aContinue reading “ENERGY AND MOMENTUM: What is the final velocity of the hovering disk?”
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”
ENERGY AND MOMENTUM: Moment of Inertia and the Parallel Axis Theorem
Inertia is a measure of a system’s ability to resist a change in motion, and it is directly proportional to a system’s massiveness. Such a system or object could be stationary with respect to an observer, or it could move with a constant velocity. When a system moves with constant velocity with respect to anContinue reading “ENERGY AND MOMENTUM: Moment of Inertia and the Parallel Axis Theorem”
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: 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”
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”
ENERGY and MOMENTUM: How Fast Will the Block Move When a Compressed Spring is Released?
Q: A spring with a spring constant k = 100 N/m is compressed a distance ( x ) = 100 mm. A block with a mass ( m ) = 0.250 kg is placed next to the spring. The surface upon which the block rests is frictionless and horizontal. When the spring and block areContinue reading “ENERGY and MOMENTUM: How Fast Will the Block Move When a Compressed Spring is Released?”
ENERGY and MOMENTUM: What is the Final Velocity of the Ball?
Q: A 10 kg iron ball moves in an Eastward direction at 5.0 m/s. It collides with a 5.0 kg rubber ball moving Northward at 10 m/s. After the collision, the iron ball moves 60° East of North with a speed of 4.0 m/s. What is the velocity of the rubber ball after the collision?Continue reading “ENERGY and MOMENTUM: What is the Final Velocity of the Ball?”
ENERGY AND MOMENTUM: Subatomic Collisions, Billiard Balls, and the 90-Degree Rule ( Part 1 )
An elastic collision, within which kinetic energy ( KE ) and momentum ( p ) are conserved, is mathematically modeled in terms of momentum as follows: pi = pf , and m1v1i + m2v2i = m1v1f + m2v2f where p = mv, and m = mass in kilograms ( kg ), and velocity ( vContinue reading “ENERGY AND MOMENTUM: Subatomic Collisions, Billiard Balls, and the 90-Degree Rule ( Part 1 )”
RENAISSANCE PHYSICS 