Τι λένε οι χρήστες - Σύνταξη κριτικής
Δεν εντοπίσαμε κριτικές στις συνήθεις τοποθεσίες.
angular points applied arms attached axle balance base beam block body called centre of gravity component contains determine diagonal direction distance divided Draw drawn effect equal equal forces equilibrium equivalent extremity feet find the centre fixed point forces act forces represented four Friction fulcrum given greater heavy Hence horizontal inches inclined plane joining keep length less lever line of action lower machine magnitude magnitude and direction measure mechanical middle point moments motion move moveable parallel parallel forces parallelogram particle passes perpendicular placed position pressure produce prove pulleys pulling radius ratio resistance resolved respectively rest resultant right angles rope round screw shew sides smooth square straight line string suppose suspended taken tend tension third three forces triangle triangle AOC turn uniform unit weight wheel
Σελίδα 27 - IV. // any number of forces acting at a point can be represented in magnitude and direction by the sides of a polygon taken in order, they will be in equilibrium.
Σελίδα 76 - Prove that the algebraic sum of the moments of two concurrent forces about any point in their plane is equal to the moment of their resultant about the same point.
Σελίδα 60 - When a body is suspended from a point, it will rest with its centre of gravity in the vertical line passing through the point of suspension.
Σελίδα 78 - The algebraic sum of the moments of two forces, meeting in a point and acting in one plane, about any point in the plane, is equal to the moment of their resultant about that point.
Σελίδα 72 - Evidently the tendency depends on the magnitude of the force and on the perpendicular distance of the line of action of the force from the point...
Σελίδα 30 - If any number of forces acting at a point can be represented in magnitude and direction by the sides of a POLYGON taken in order, they are in equilibrium.
Σελίδα 107 - ... and a man in the basket support himself and the basket, by pulling at the free end of the string, find the tension he exerts, neglecting the inclination of the string to the vertical, and assuming the weight of the man and basket to be W. 6. A man, whose weight is 12 stone, raises 3 cwt. by means of a system of pulleys in which the same string passes round all the pulleys, there being 4 in each block, and the string being attached to the upper block; neglecting the weights of the pulleys, find...
Σελίδα 15 - We proceed to establish an important theorem which enables us to determine the resultant of any two forces acting at a point : the theorem is called the parallelogram of forces, and may be thus enunciated. If two forces acting at a point be represented in magnitude and direction by two straight lines drawn from that point, and if a parallelogram be constructed having these two lines for adjacent sides, then that diagonal of the parallelogram which passes through the point of application of the forces...
Σελίδα 13 - For, first, suppose that while the horses are pulling at the stone the traction-engine is applied to the opposite side of the stone, so as to pull the stone with the same drawing-power as that of the horses. Then the force exerted by the engine will counteract the forces exerted by the horses, and the three forces will be in equilibrium. Then also it is plain that when three forces are in equilibrium, one of them is equal' and opposite to the resultant of the other two.