An elementary treatise on mechanicsLongmans, Green and Company, 1889 |
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Συχνά εμφανιζόμενοι όροι και φράσεις
angle of 30 angle of friction attached axis balance centre of gravity Chap circumference coefficient of friction common Concurrent Forces condition of equilibrium coplanar cord cylinder determine distance equal and opposite equilibrate equilibrium EXERCISES false balance feet long feet per second forces acting fulcrum horizontal force horizontal plane inches intersection length lower block magnitude and direction mechanical advantage middle point motion movable pulleys P₁ P₂ parallel forces parallelogram Parallelogram of Forces particle perpendicular point of application pressure radius reaction represented resistance respectively rest right angles rigid body rough inclined plane round rowlock scale-pan screw sides single force smooth inclined plane smooth plane Statical statical friction steelyard support a weight surface system of pulleys taking moments teeth tons triangle uniform beam velocity vertical w₁ wedge weight of 12 wheel and axle whence
Δημοφιλή αποσπάσματα
Σελίδα 26 - 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 109 - Ibs. weight, in equilibrium, it being given that the force, the reaction of the plane, and the weight of the body are in arithmetical progression. 9. A number of loaded trucks, each containing 1 ton, on one part of a tramway inclined at an angle a to the horizon supports an equal number of empty trucks on another part whose inclination is j3. Find the weight of a truck. 10. A body, of weight 50 Ibs., is in equilibrium on a smooth plane inclined at an angle of 20° 20...
Σελίδα 127 - J31', %P, act on a particle : find the angles between their respective directions so that there may be equilibrium. 10. Find the condition of equilibrium in the system of pulleys in which one string passes round two sets of pulleys, each set fixed in a block. A man of 12 stone raises 3 cwt. by means of such a system of pulleys, there being 4 in each block. Neglecting the weight of the pulleys find his pressure on the ground if he pull vertically. 11. Define the Centre of Inertia (centre...
Σελίδα 27 - The moment of a force about a point is the product of the force and the perpendicular distance from the line of action of the force to the point.
Σελίδα 122 - In a system in which each pulley hangs by a separate string and the strings are parallel, there is an equilibrium when P : W :: 1 : that power of 2 whose index is the number of moveable pulleys.
Σελίδα 63 - D are the angles of a parallelogram taken in order; like parallel forces proportional to 6, 10, 14, and 10 respectively act at A, B, C and D ; shew that the centre and resultant of these parallel forces remain the same, if, instead of these forces, parallel forces, proportional to 8, 12, 16 and 4, act at the points of bisection of the sides AB, BC, CD, and DA respectively. 83. Given the centre of gravity of the two portions of a body, to find the centre of gravity of the whole body. Let the given...
Σελίδα 64 - ... cone on the same base and of half the height of the original cone; find the position of the centre of gravity of the cone so formed.
Σελίδα 43 - couple about any point in the plane of the couple is equal to the algebraic sum of the moments of the two forces composing the couple about the same point.
Σελίδα 84 - ... straight lever, the weight of the lever being neglected. A uniform straight lever, 4 feet long, weighs 10 Ibs., the fulcrum is at one end ; find what upward force acting at the other end will keep the lever horizontal when a weight of 10 Ibs. is hung at a distance of I foot from the fulcrum. Find also the pressure on the fulcrum and the direction in which it acts. (S. and A. Exam. 1891.) Am.
Σελίδα 61 - A short circular cylinder of wood has a hemispherical end. When placed with its curved end on a smooth table it rests in any position in which it is placed. Determine the position of its centre of gravity.