Mechanical Design Handbook

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Showing posts from February, 2008

Improve math skills of your kids - Learn step-by-step arithmetic from Math games

Math: Unknown - Step-by-step math calculation game for iOS.

Download on the App Store | Facebook | Website

Math: Unknown is much more than a math game. It is a step-by-step math calculation game which will teach users how to calculate in the correct order rather than just asking only the final calculated results.

The app consists of four basic arithmetic operations which are addition, subtraction, multiplication and division. In order to get started, users who are new to arithmetic can learn from animated calculation guides showing step-by-step procedures of solving each type of operation. It is also helpful for experienced users as a quick reference.

Generally, addition and subtraction may be difficult for users who just start learning math especially when questions require carrying or borrowing (also called regrouping). The app helps users to visualize the process of carrying and borrowing in the way it will be done on paper. Once users understand how these operations work, they are ready to learn multiplication and division.

For most students, division is considered as the most difficult arithmetic operation to solve. It is a common area of struggle since it requires prior knowledge of both multiplication and subtraction. To help users understand division, the app uses long division to teach all calculation procedures. Relevant multiplication table will be shown beside the question. Users will have to pick a number from the table which go into the dividend. Multiplication of selected number and divisor is automatically calculated, but the users have to do subtraction and drop down the next digit themselves. Learning whole calculation processes will make them master it in no time.

Math: Unknown is a helpful app for students who seriously want to improve arithmetic calculation skills.

Timing Belts

Timing belts solve the slip problems of flat, O ring, and V belts by using a flexible tooth, molded to a belt that has tension members built in. The teeth are flexible allowing the load to be spread out over all the teeth in contact with the pulley. Timing belts are part of a larger category of power transmission devices called synchronous drives . These belt or cable-based drives have the distinct advantage of not slipping, hence the name synchronous. Synchronous or positive drive also means these belts can even be used in wet conditions, provided the pulleys are stainless steel or plastic to resist corrosion. Timing belts come in several types, depending on their tooth profile and manufacturing method. The most common timing belt has a trapezoidal shaped tooth. This shape has been the standard for many years, but it does have drawbacks. As each tooth comes in contact with the mating teeth on a pulley, the tooth tends to be deflected by the cantilever force, deforming the belt’s teeth