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For speeds on the order of 100 km/h there is also the more or less equivalent rule that the stopping distance be the speed divided by 2 k/h, referred to as halber tacho (half the speedometer) rule, e.g. for 100 km/h the stopping distance should be about 50 m. Additionally, German driving schools teach their pupils that the total stopping ...
Aitken (1977) assumes that 1 h takes to cover 3 mi (5 km) on paths, tracks and roads, while this is reduced to 2½ mi (4 km) on all other surfaces. [5] For both distances he gives an additional 1 h per 2000 ft (600 m) of ascent. [5] So Aitken doesn't take into account equivalence between distance and climb (proposed by Scarf in 1998 [4] [6]).
This is not exactly a Cooper test but a reasonable practical compromise as long as the distance is of sufficient length to put a continuous load on the cardiovascular system for 10 or more minutes. For example, the British Army uses 1.5 miles, the Australian Army uses 2.4 kilometers, the US Army uses 2 miles and the US Marine Corps 3 miles.
The actual Hill radius for the Earth-Moon pair is on the order of 60,000 km (i.e., extending less than one-sixth the distance of the 378,000 km between the Moon and the Earth). [ 9 ] In the Earth-Sun example, the Earth ( 5.97 × 10 24 kg ) orbits the Sun ( 1.99 × 10 30 kg ) at a distance of 149.6 million km, or one astronomical unit (AU).
Although most contemporary accounts used an Arabic mile of 6 444 feet (1,964 metres), which gave a Spanish league of the degree of 25,776 feet (7,857 metres or 4.242 modern nautical miles) others defined an Arabic mile as just 6,000 feet making a Spanish league of the degree 24,000 feet (or 7,315 metres, almost exactly 3.95 modern nautical miles).
A metric or distance function is a function d which takes pairs of points or objects to real numbers and satisfies the following rules: The distance between an object and itself is always zero. The distance between distinct objects is always positive. Distance is symmetric: the distance from x to y is always the same as the distance from y to x.
Speed has the dimensions of distance divided by time. The SI unit of speed is the metre per second (m/s), but the most common unit of speed in everyday usage is the kilometre per hour (km/h) or, in the US and the UK, miles per hour (mph). For air and marine travel, the knot is commonly used.
The ancient Greek understanding of physics was limited to the statics of simple machines (the balance of forces), and did not include dynamics or the concept of work. During the Renaissance the dynamics of the Mechanical Powers, as the simple machines were called, began to be studied from the standpoint of how far they could lift a load, in addition to the force they could apply, leading ...