The plan of speeds is built to solve problems of determination of speeds of points of a body graphically. In mathematics and descriptive geometry it represents the chart in which all directions of speed (V) points of a solid body or a certain mechanism are postponed from one place in a certain scale.
Instruction
1. Plan this it is characterized certain properties: in it are always mutually perpendicular a piece which connects the terminations of the directed points on the surface of a body - to a piece which connects these points. Length of pieces which unite the terminations of vectors of speed of certain points of a body is to the proportional length of pieces which unite the points corresponding to these vectors.
2. What will more choose the scale of the plan in which vectors of V are under construction, especially the answer to a solvable task will turn out exact - respectively, at the small scale the answer received during measurements and the subsequent calculation will be approximate.
3. How to construct the geometrical plan, it is the simplest to explain on a concrete example as construction and further calculation takes place in each case differently. In general, for creation of the similar plan needs to know, at least, a speed at least one of points of a figure or the mechanism and also the direction of a vector of speed of any other point of creation of the chart.
4. Let there is an ABVG mechanism consisting of the cores connected by hinges. Let t speed. In it is known, and is equal to 2 m/s, and V is a perpendicular to GV piece, and a vector of B - it is perpendicular to AB. It is required to find t speed. B.
5. In randomly the chosen point postpone a mechanism pole - t. Oh, then choose necessary scale. Further vector of the V t. In it is necessary to transfer so that the beginning of this vector coincided with t. Oh, and it is necessary to transfer it in parallel. Draw a straight line of ODES which will proceed from a pole and will be perpendicular to a piece OH.
6. From the end of a vector of the V t. In draw a straight line which will make a perpendicular for BV. The drawn straight line will cross another - ODES. A point in which these straight lines were crossed, define as b.
7. From the received piece About also calculate t speed. Б: for this purpose precisely measure piece length About, and then multiply its length with a scale of creation of the drawing in relation to a real body or a detail - the t.B speed module will turn out