A bowling ball is a piece of sporting equipment used to hit bowling pins in the sport of bowling. Ten-pin bowling balls are typically hard spheres with three holes drilled in them, one each for the ring and middle fingers, and one for the thumb. Regulating bodies such as the USBC maintain requirements for the properties of bowling balls, including size, hardness, and number of holes, as well as maintaining a list of bowling balls approved for competitive play. Other bowling balls, such as those used in five-pin bowling, candlepin bowling, and duckpin bowling are smaller, lighter, and without holes, so that they may be held in the palm of the bowler's hand. Most bowling alleys provide balls for patrons to use within the establishment, often referred to as "house balls."
Key properties of ten-pin bowling balls include surface friction, porosity, and mass distribution, which affect the motion of the ball as it rolls. These properties are varied to control how much a ball will slide through the oily surface of a typical bowling lane, and how easily a ball will change direction when the roll is combined with rotational motion. Friction and porosity are variables of the surface of the ball, known as the "cover stock," while mass distribution is determined by the shape and size of the core.
Golf equipment encompasses the various items that are used to play the sport of golf. Types of equipment include the golf ball itself, implements designed for striking the golf ball, devices that aid in the process of playing a stroke, and items that in some way enrich the playing experience.
Originally, golf balls were made of a hardwood, such as beech. Beginning between the 14th and 16th centuries, more expensive golf balls were made of a leather skin stuffed with down feathers; these were called "featheries". Around the mid-1800s, a new material called gutta-percha, made from the latex of the East Asian sapodilla tree, started to be used to create more inexpensive golf balls nicknamed "gutties", which had similar flight characteristics as featheries. These then progressed to "brambles" in the later 1800s, using a raised dimple pattern and resembling bramble fruit, and then to "meshies" beginning in the early 1900s, where ball manufacturers started experimenting with latex rubber cores and wound mesh skins that created recessed patterns over the ball's surface. Recessed circular dimples were patented in 1910, but didn't become popular until the 1940s after the patents expired.
Ek = Et+Er
In physics, the kinetic energy of an object is the energy which it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes. The same amount of work is done by the body in decelerating from its current speed to a state of rest.
A golf ball is a special ball designed to be used in the game of golf.
Under the rules of golf, a golf ball weighs no more than 1.620 oz (45.93 grams), has a diameter not less than 1.680 in (42.67 mm), and performs within specified velocity, distance, and symmetry limits. Like golf clubs, golf balls are subject to testing and approval by the R&A (formerly part of the Royal and Ancient Golf Club of St Andrews) and the United States Golf Association, and those that do not conform with regulations may not be used in competitions (Rule 5–1).
Fast bowling, sometimes known as pace bowling, is one of the two main approaches to bowling in the sport of cricket. The other is spin bowling. Practitioners are usually known as fast bowlers, fastmen, pace bowlers, or pacemen, although sometimes the label refers to the specific fast bowling technique the bowler prefers, such as swing bowler or seam bowler.
The aim of fast bowling is to bowl the hard cricket ball at high speed and to induce it to bounce off the pitch in an erratic fashion or move sideways through the air, factors which make it difficult for the batsman to hit the ball cleanly. A typical fast delivery has a speed in the range of 137–153 km/h (85–95 mph).
Swing bowling is a technique used for bowling in the sport of cricket. Practitioners are known as swing bowlers. Swing bowling is generally classed as a subtype of fast bowling.
The essence of swing bowling is to get the cricket ball to deviate sideways as it moves through the air towards or away from the batsman. In order to do this, the bowler makes use of five factors: