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Showing posts with the label Mechanics

Thermal stress equation

Thermal stress refers to the mechanical stress or strain that occurs in a material as a result of a change in temperature . When a material is exposed to a temperature differential or undergoes a temperature change, it tends to expand or contract. However, different parts of the material may expand or contract at different rates, leading to internal stresses. Thermal stress equation The basic thermal stress equation is : σ = EαΔT Where: σ = Thermal stress (Pa) E = Young's modulus of elasticity (Pa) α = Coefficient of thermal expansion (K-1) ΔT = Change in temperature (K or °C) This gives the stress developed in a material or structure when it undergoes a temperature change ΔT. To derive this thermal stress equation: Strain (ε) is proportional to the temperature change : ε = αΔT Stress (σ) is proportional to strain by the elastic modulus : σ = Eε Substituting the first equation into the second gives : σ = EαΔT This simple linear elastic model assumes the stress is b...

Oblique collision

An oblique collision occurs when two objects collide at an angle other than 0° or 180 °. In an oblique collision between two objects, object 1 and object 2, the initial velocities of the objects form an angle θ. According to the law of conservation of momentum, the total momentum before and after the collision remains constant. However, the direction of momentum changes due to the angular nature of the collision. m 1 u 1   + m 1 u 2  = m 1 v 1   + m 2 v 2 Where m is mass, u is initial velocity, and v is final velocity. The velocity vectors can be resolved into perpendicular and parallel components to the surface at the point of collision. The parallel components remain unchanged. m 1  u 1  cosθ = m 2  v 2  cosφ m 1  u 1  cosθ = m 2  v 2  cosφ The perpendicular components are related by the coefficient of restitution (e). m 1  u 1   sinθ = -m 2  v  2  sinφ m 1  u 1   sinθ = m 2  v 2  sinφ By analyzing the momentum and velocity components along with conservation of energy, the...

Centre of Mass of Solid Cone

Understanding the location of the center of mass in solid objects is an important concept in physics. For uniform three-dimensional shapes like a cone, finding the center of mass is straightforward with some basic geometry. In this article, we'll walk through the step-by-step method to locate the center of mass along the central axis of a solid cone. Knowing this helps predict the cone's balance point and stability. Key Facts About a Solid Cone: - The density and mass are evenly distributed throughout the volume - It has circular base of radius r - The height from base to apex is h - Total mass is m Using Symmetry to Find the Center of Mass: The center of mass of any solid lies along its axis of symmetry. For a vertically standing cone, the center of mass will be along the central vertical axis. The bottom section of the cone closer to the base contains more mass than the top. But due to the even density, we can balance the mass distribution. The bottom section accounts...

The Centre of Mass of a System of Three Particles

Here is a draft article about calculating the center of mass for a system of three particles: Finding the Center of Mass for a Three Particle System Determining the center of mass location is critical in physics for simplifying analysis of rigid body motion and forces. For a system of discrete particles, the center of mass coordinates can be calculated by taking a weighted average of the individual particle positions. This article explains how to find the center of mass for a system of three particles. Defining the Three Particle System Consider three point mass particles fixed in space, labeled A, B and C. Each has a known mass, mA, mB, and mC, and particle positions given by coordinate vectors rA, rB, and rC. The goal is to determine the center of mass position vector rcm for the system. Summing the Mass The total mass M of the three particle system is found by simply summing the individual masses: M = mA + mB + mC This total mass will help weigh the contributions of each par...

Centre of mass of semicircular disc

Here is a draft article about calculating the center of mass of a semicircular disc: Finding the Center of Mass of a Semicircular Disc Determining the center of mass of objects with complex shapes is an important skill in physics and engineering. The center of mass represents the balance point of an object's mass distribution. For a semicircular disc, calculating the exact coordinates requires integration methods. This article will show the step-by-step method to locate the center of mass of a semicircular disc . Defining a Semicircular Disc A semicircular disc is a two-dimensional shape formed by slicing a circular disc in half along its diameter. It resembles a flat half-circle. The disc has a radius r and a total mass m evenly distributed across its area. To find the center of mass, we consider small mass elements dm making up the semicircle. Using Symmetry to Simplify The semicircle's axis of symmetry divides it into two mirrored halves. This symmetry tells us the cen...

Motion of centre of mass

# Demystifying Center of Mass Motion: Your Guide to this Essential Physics Concept The center of mass is a crucial concept in dynamics and mechanics. Understanding how an object's center of mass moves provides deep insight into its overall motion. In this article, we break down center of mass, see how to calculate it, and explore applications from sports to spacecraft. Strap in for a tour of center of mass motion fundamentals! Defining the Center of Mass The center of mass is the weighted average location of an object's mass. For simple shapes with uniform density, it's at the geometric center. For complex shapes, calculate center of mass by taking the sum of each mass element's position, weighted by its mass fraction. Dividing by total mass gives the overall center of mass. Center of mass sits at the balance point where the object can be perfectly balanced. This rarely aligns with the geometric center for irregular objects. Not to be confused with center of gravi...