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Steven Holzner
Dr. Steven Holzner has written more than 40 books about physics and programming. He was a contributing editor at PC Magazine and was on the faculty at both MIT and Cornell. He has authored Dummies titles including Physics For Dummies and Physics Essentials For Dummies. Dr. Holzner received his PhD at Cornell.
Articles & Books From Steven Holzner
Article / Updated 03-20-2024
Physics is filled with equations and formulas that deal with angular motion, Carnot engines, fluids, forces, moments of inertia, linear motion, simple harmonic motion, thermodynamics, and work and energy.Here’s a list of some important physics formulas and equations to keep on hand — arranged by topic — so you don’t have to go searching to find them.
Article / Updated 03-20-2024
Physics constants are physical quantities with fixed numerical values. The following list contains the most common physics constants, including Avogadro’s number, Boltzmann’s constant, the mass of electron, the mass of a proton, the speed of light, the gravitational constant, and the gas constant.
Avogadro’s
Article / Updated 03-20-2024
When an object moves in a circle, if you know the magnitude of the angular velocity, then you can use physics to calculate the tangential velocity of the object on the curve.At any point on a circle, you can pick two special directions: The direction that points directly away from the center of the circle (along the radius) is called the radial direction, and the direction that’s perpendicular to this is called the tangential direction.
Article / Updated 03-20-2024
In physics, how much torque you exert on an object depends on two things: the force you exert, F; and the lever arm. Also called the moment
arm, the lever arm is the perpendicular distance from the pivot point to the point at which you exert your force and is related to the distance from the axis, r, byis the angle between the force and a line from the axis to the point where the force is applied.
Article / Updated 03-20-2024
In physics, you can examine how much potential and kinetic energy is stored in a spring when you compress or stretch it. The work you do compressing or stretching the spring must go into the energy stored in the spring. That energy is called elastic potential energy and is equal to the force, F, times the distance, s:W = FsAs you stretch or compress a spring, the force varies, but it varies in a linear way (because in Hooke’s law, force is proportional to the displacement).
Article / Updated 03-20-2024
In physics, you can apply Hooke’s law, along with the concept of simple harmonic motion, to find the angular frequency of a mass on a spring. And because you can relate angular frequency and the mass on the spring, you can find the displacement, velocity, and acceleration of the mass.Hooke’s law says thatF = –kxwhere F is the force exerted by the spring, k is the spring constant, and x is displacement from equilibrium.
Article / Updated 07-31-2023
In physics, it’s important to know the difference between conservative and nonconservative forces. The work a conservative force does on an object is path-independent; the actual path taken by the object makes no difference. Fifty meters up in the air has the same gravitational potential energy whether you get there by taking the steps or by hopping on a Ferris wheel.
Article / Updated 06-28-2023
Thanks to the principle of conservation of mechanical energy, you can use physics to determine the final height of a moving object. At this very moment, for example, suppose Tarzan is swinging on a vine over a crocodile-infested river at a speed of 13.0 meters/second. He needs to reach the opposite river bank 9.
Article / Updated 12-23-2022
Any physicist knows that if an object applies a force to a spring, then the spring applies an equal and opposite force to the object. Hooke’s law gives the force a spring exerts on an object attached to it with the following equation:F = –kxThe minus sign shows that this force is in the opposite direction of the force that’s stretching or compressing the spring.
Article / Updated 10-06-2022
At some point, your quantum physics instructor may want you to add time dependence and get a physical equation for a three-dimensional free particle problem. You can add time dependence to the solution forif you remember that, for a free particle,That equation gives you this form forBecausethe equation turns intoIn fact, now that the right side of the equation is in terms of the radius vector r, you can make the left side match:That’s the solution to the Schrödinger equation, but it’s unphysical.