Consider any four wheel automobile (say, car) having wheels A, B, C and D, taking a turn towards left on a curved path, as shown in Fig (a). The wheels A and C are inner wheels, whereas B and D are outer wheels. While the vehicle will move in a straight line there will not
Stability of a Four Wheel Moving in Curved Path Read More »
Before discussing the gyroscopic effect on naval ships, first let us brief the terminology used in connection with the naval ship. Ship Terminology The front, top, and side views of a naval ship are shown in fig (a), (b) and (c) respectively. The terms used are: Bow: It is the fore or front end of
Gyroscopic Effect on Naval Ship (or Sea Vessels) Read More »
We already know that the angular acceleration is the rate of change of angular velocity. It is a vector quantity and can be represented both in magnitude and direction with the help of right hand screw rule. A body rotating in a plane about a fixed axis is subjected to the angular acceleration. But whenever
Precessional Angular Motion – Pedagogy Zone Read More »
The spring controlled governor of the Wilson Hartnell type is shown in Fig. In this governor, the bell crank levers are pivoted at the ends of two arms which rotate with the spindle. The vertical arms of the bell crank lever support the balls and horizontal arms are attached to the sleeve through rollers. The
Wilson Hartnell Governor (Radial Spring Governor) Read More »
Figure shows a simplified overview of the database design process. The first step shown is requirements collection and analysis. During this step, the database designers interview prospective database users to understand and document their data requirements. The result of this step is a concisely written set of users’ requirements. These requirements should be specified in
Using High Level Conceptual Data Models for Database Design Read More »
In this section, we give an overview of the schema evolution commands available in SQL, which can be used to alter a schema by adding or dropping tables, attributes, constraints, and other schema elements. This can be done while the database is operational and does not require recompilation of the database schema. Certain checks must
Schema Change Statement in SQL Read More »
Governor Arrangement This is the most common type of governor. In the centrifugal type governors, rotation of the crank shaft is taken to a vertical spindle through suitable gears. It consists of two balls of equal mass, which are attached to the arms as shown in Fig. These balls are known as governor balls or
Centrifugal Governors – Principle of Working Read More »
Function of Governor The function of a governor is to automatically maintain the speed of an engine within specified limits whenever there is a variation of load. If the load on the engine increases, its speed decreases. So it becomes necessary to increase the fuel supply by opening the throttle valve. On the other hand,
Governor Vs Flywheel – Pedagogy Zone Read More »
In this section we introduce the concept of a view in SQL. We show how views are specified, and then we discuss the problem of updating views (Virtual Tables) and how views can be implemented by the DBMS. Concept of a View in SQL A view in SQL terminology is a single table that is
View (Virtual Tables) in SQL – Pedagogy Zone Read More »
So far, we have discussed the free vibrations of systems where a system once disturbed from its equilibrium position executes vibration indefinitely because of its elastic properties. In actual practice, this system will come to rest, sooner or later, depending upon the amount of damping present in the system. In case of forced vibrations, the
Forced Vibrations with Harmonic Excitation Read More »