![]() ![]() (i) a stroke is direct when the cue-ball strikes an object ball without first striking a cushion (d) A stroke may be made directly or indirectly, thus: (c) A stroke is not completed until all balls have come to rest. (b) A stroke is fair when no infringement of Rule is made. (a) A stroke is made when the striker strikes the cue-ball with the tip of the cue. The person about to play or in play is the striker and remains so until the referee has decided he has left the table at the end of his turn. Stringing is when both players (or one from each side) play together from the Baulk-line on either side of the “D” to the top cushion, with the object of leaving the ball played closer to the bottom cushion that the ball played by the opponent. (b) The other white ball and the red are object balls. (a) The cue-ball is the ball of the striker (c) being awarded by the referee under Section 4 Rule 2.Ī match is an agreed or stipulated number of games. (b) either side reaching the number of points specified, or (a) reaching the end of a specified period of time, ![]() All extensions, adaptors and other devices to aid cueing must be of a design approved by the WPBSA.Ī game is the period of play from the opening stroke until it is completed by These may form part of the equipment normally found at the table but also include equipment introduced by either player or the referee (see also Section 3 Rule 18). Various cue rests, long cues (called butts and half-butts according to length), extensions and adaptors may be used by players faced with difficult positions for cueing. (b) a set of balls may be changed by agreement between the players or on a decision by the referee.Ī cue shall be not less that 3ft (914mm) in length and shall show no substantial departure from the traditional and generally accepted shape and form. (a) they shall be of equal weight within a tolerance of 0.5g per set The balls shall be of an approved composition and shall each have a diameter of 52.5mm with a tolerance of +/_ 0.05mm and: ![]() (iii) the Pyramid Spot, located midway between the Centre Spot and the face of the top cushion. (ii) the Centre Spot, located midway between the faces of the top and bottom cushions. (i) the Spot, 12¾in (324mm) from a point perpendicularly below the face of the top cushion. ![]() (f) Four spots are marked on the centre longitudinal line of the table: (e) The “D” is a semi-circle described in Baulk with its centre at the middle of the Baulk-line and with a radius of 11½in (292mm). (d) A straight line drawn 29in (737mm) from the face of the bottom cushion and parallel to it is called the Baulk-line, and that line and the intervening space is termed the Baulk. (ii) The pocket openings shall conform to the templates authorised by the World Professional Billiards and Snooker Association (WPBSA). (c) (i) There shall be pockets at the corners (two at the Spot end known as the top pockets and two at the Baulk end known as the bottom pockets) and one each at the middle of the longer sides (known as the centre pockets). (b) The height of the table from the floor to the top of the cushion rail shall be from 2ft 9½in to 2ft 10½in (851mm to 876mm). (a) The playing area within the cushion faces shall measure 11ft 8½in x 5 ft 10in (3569mm x 1778mm) with a tolerance on both dimensions of +/_ ½in (+/_ 13mm). Measurements in parentheses state the metric equivalent to the nearest millimetre Thus, the angle between the direction of motion of the second ball and the original direction of motion of the cue ball ϕ is 41. Substitute the values in the above expression, and we get,ģ. V i 1 + v i 2 = v f 1 sin θ + v f 2 sin ϕ 0 = v f 1 sin θ + v f 2 sin ϕ v f 1 sin ( 22 ° ) = v f 2 sin ϕ (2) Initially, the second ball is at rest we can write, V i 1 + v i 2 = v f 1 cos θ + v f 2 cos ϕ Where ϕ is the angle of the second ball after the collision, and are the initial velocities of the balls, and masses are the same for both the balls so that we can cancel them as, M 1 v i 1 + m 2 v i 2 = m 1 v f 1 cos θ + m 2 v f 2 cos ϕ We can write two equations of conservation of momentum for x and y directions. ![]()
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