# Tip 1: How to calculate the lever

lever - an ancient mechanism for lifting.It is a bar that rotates around the fulcrum.Despite the fact that it is very much all other devices, the lever has not lost its relevance.It is an integral part of many of today's devices.For these devices to work, you need to calculate the length of the lever arm in the same way as it has done ever Archimedes. lever and used in more ancient times, but the first written explanation left is just a great Greek scholar.That he tied together the length of the lever arm, force and load.
you need
• devices:
• - a device for measuring length;
• - Calculator.
• mathematical and physical formulas and concepts:
• - the law of conservation of energy;
• - definition of the lever arm;
• - definition of force;
• - properties of similar triangles;
• - weight of the load to be moved.
Guide
1
Draw a diagram of the lever, denoting her forces F1 and F2, acting on both of his shoulders.Designate the lever arms as the D1 and D2.The shoulders are designated from the fulcr
um to the point of application of force.The scheme build two right-angled triangles, their legs will be the distance that you want to move one arm and which moves with the other arm and the actual lever arms and the hypotenuse - the distance between the point of application of force and the fulcrum.You will turn these triangles, as in the case of application of force to one arm of the second deviates from the initial horizontal at exactly the same angle as the first.
2
Calculate the distance that you must move the lever.If you are given a real lever to be moved to the actual distance, simply measure the length of the desired length with a ruler or tape measure.Mark this distance as Δh1.
3
Calculate the work that must make the force F1, to move the lever to the right you away.Work is calculated according to the formula A = F * Δh, in this case, the formula would look like A1 = F1 * Δh1, where F1 - the force acting on the first arm and Δh1- already known distance.For the same formula, calculate the work that must make the force on the second lever arm.This formula will look like A2 = F2 * Δh2.
4
Remember the law of conservation of energy for a closed system.The work makes a force acting on the first lever arm, should be equal to that which it makes an opposing force on the second lever arm.That is, it turns out that A1 = A2, and F1 * Δh1 = F2 * Δh2.
5
Remember aspect ratio in similar triangles.The ratio of the legs of one of them is the ratio of the legs of another, that is Δh1 / Δh2 = D1 / D2, where D - the length of one and the other arm.Replacing relation to their peers in their respective formulas, we get the following equation: F1 * D1 = F2 * D2.
6
Calculate the gear ratio I. It is the ratio of the load and the force applied to move it, that is, i = F1 / F2 = D1 / D2.

# Tip 2: How to calculate the shoulder

When Knitting are various models of parts cut pullovers, dresses, jackets and other items from the line of the shoulders.They may have a rectangular shape and back before or documented so-called shoulder bevel.To look more elegant clothes, the right and left sides of the upper part of the need to gradually diminish the loop.It is important to calculate the sequence of the decrease, whereas the product will fall exactly on the figure.
you need
• - line;
• - paper;
• - pencil;
• - knitting pattern;
• - straight spokes;
• - yarn.
Guide
1
Draw on the paper chart the future subtraction of loops to create a sloping shoulder line.Suffice it to represent only the right side of the pattern.It will include a half neck shelves, as well as drawing the desired bevel shoulder dress.Other details (one front and two rear left upper arm) will be easy to perform on this template.
2
Inside drawing must construct a rectangular triangle.His sharp angle formed at the point of the beginning of the subtraction of loops for the bevel shoulder;swipe away a flat horizontal line.From the top of the slope (as a rule, it is also the highest point of neckline items) Spend a perpendicular line.The horizontal and perpendicular crossed - triangular figure for the calculation of the shoulder is ready.
3
Specify the density of the finished knitting pattern, perform basic knitting pattern.You should have a square piece of fabric 10 by 10 cm. It is important to know how many rows of knitting is one side of the square (the height), and how many loops included in its other side (lower part).
4
Count on the ground to draw a triangle to calculate the number of loops of the shoulder that you need close at vyvyazyvanii bias.And the height of the figure you know the number of rows in which the closed loop.Note: the loop right shoulder you close only at the beginning of the facial series, and the left - on the contrary, at the beginning of backstitches.Therefore, one group will have to close the loop through a series.
5
When you provyazhete two series of paintings on the sides will bead braid.By the number of braids can see how much is needed to close the loop at a time.To this end the total number of loops of each arm (they enter the base of the triangle) to be divided by the number of braids disposed height of the triangular shape.
6
Try to calculate the decrease loops to tilt the shoulder by a concrete example, and complicated at first glance, the system of calculation becomes evident.For example, the base of the triangle have hinge part 39, and along its height are 16 rows (or 8 pigtails).39: 8 = 4 and 7 will hinge to the residue.These remaining loops are divided into groups, one in each.So, for knitting line sloping shoulders, you need to close 7 times for 5 loops, and once - just 4 loops.