inertia and mechanisms FREE STUDY（惯性和机制,免费学习）.pdf

SOLID MECHANICS DYNAMICS TUTORIAL – INERTIA FORCES IN MECHANISMS This work covers elements of the syllabus for the Engineering Council Exam D225 – Dynamics of Mechanical Systems C103 Engineering Science. This tutorial examines the relationship between inertia and acceleration. On completion of this tutorial you should be able to • Define inertia force. • Calculate the force required to accelerate components in a mechanism. • Consider the effect of friction on the acceleration. • Use the system approach to solve forces in a mechanism. It is assumed that the student is already familiar with the following concepts. • Newton’s Laws of Motion. • The laws relating displacement, velocity and acceleration. • Coulomb’s Laws of Friction. • The representation of forces by a vector. • The resolution of forces into two perpendicular components. • The forms of mechanical power and energy. All the above may be found in the pre-requisite tutorials. © D.J.DUNN 1 1.1. FORCE, MASS AND ACCELERATION We have all probably observed that objects with large masses require more force to accelerate them than objects with small masses. This is why, for example, large vehicles need larger engines than small vehicles. The reluctance of a body to speed up or slow down is in direct proportion to the mass and the effect is known as inertia. Newton showed that the relationship between Force (F), mass (m) and acceleration (a) is F = m a From this relationship we get the definition of force. A force of 1 Newton is that required to accelerate a mass of 1 kg at 1 m/s2. It follows that the Newton is a de