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Speed [length/time]



Speed in Sports
Record time for Men's 100 meters = 9.85 seconds -- that's about 22.71 miles/hour.

Recent mile record = 3:47.69 -- that's about 15.81 miles /hour.

Let's say you run a 5K in 20 minutes -- that's about 9.32 miles/hr, about a 6:26 minutes/mile pace.

Let's say you do a 10K in 42 minutes -- that's about 8.88 miles/hour, a little faster than a 6:45 minutes per mile pace.

Recent Marathon* record = 2 hr 08:47 -- that's about 12.22 miles/hour, a little faster than a 4:54-minute per mile pace for 26.2 miles.

 A men's swimming record for the 50 meters Freestyle = 21.81 seconds -- that's about 5.12 miles/hour

Sprint 7:00/mi (8.5 mph)
Run = 7:00 - 9:00/mi (8.5 - 6.6. mph)
Jog = 9:00 - 11:00/mi (6.6 mph - 5.4 mph)
Speed Walk = 11:00 - 16:00/mi - 20:00/mi
(5.4 mph - 3.7 mph - 3.0 mph)

* Marathon distance = 26 miles, 385 yards (26.2188 miles)


60,000 hours = 6.8 years
80,000 hours = 9.1 years

Speed and Velocity Defined
Speed is the rate of motion or the rate of change in position, expressed as distance(d) traveled per unit of time(t).

Speed is a scalar quantity with dimensions distance/time; the equivalent vector quantity to speed is known as velocity. Speed is measured in the same physical units of measurement as velocity, but does not the directional information of velocity. Speed is a magnitude component of velocity.

In physics, acceleration (a) is defined as the rate of change (or derivative with respect to time) of velocity. Acceleration is a vector quantity with dimension length/time². In SI units, acceleration is measured in metres/second² (m·s-²) using an accelerometer.

Every planetary body, including the Earth, is surrounded by its own gravitational field, which exerts an attractive force on any object. This field is proportional to the body's mass and varies inversely with the square of distance from the body. The gravitational field is numerically equal to the acceleration of objects under its influence.

Gravity at Earth's surface (g) is approximately 9.8 m/s². Without air resistance, an object falling freely near the earth's surface increases in speed by 9.807 m/s (32.174 ft/s or 22 mi/h) for each second of its descent.

For example, an object starting from rest will attain a speed of 9.807 m/s (32.17 ft/s) after one second, 19.614 m/s (64.34 ft/s) after two seconds, and so on. According to Newton's Third Law, the Earth itself experiences an equal and opposite force to that acting on the falling object, meaning that the Earth also accelerates towards the object. However, because the mass of the Earth is huge, the measurable acceleration of the Earth by this same force is negligible, when measured relative to the system's center of mass (the system being the Earth and the object interacting).

Newton's Three Laws of Motion
First Law (Law of Inertia) "An object at rest tends to stay at rest."

If no external force acts on a particle, then it is possible to select a set of reference frames, called inertial reference frames, observed from which the particle moves without any change in velocity.

Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it.

Second Law (Law of Momentum) an object accelerates in direct proportion to the force applied to it.

Observed from an inertial reference frame, the net force on a particle is proportional to the time rate of change of its linear momentum. Momentum is the product of mass and velocity. This law is often stated as F = ma (the force on an object is equal to its mass multiplied by its acceleration).

The relationship between an object's mass m, its acceleration a, and the applied force F is F = ma. Acceleration and force are vectors (as indicated by their symbols being displayed in slant bold font); in this law the direction of the force vector is the same as the direction of the acceleration vector.

When a force acts on a body, the body's momentum is changed by an amount that is proportional to the applied force and the amount of time the force acts on the body.

Third Law (Law of Reaction) "For every action, there is an equal and opposite reaction.

Whenever A exerts a force on B, B simultaneously exerts a force on A with the same magnitude in the opposite direction. The strong form of the law further postulates that these two forces act along the same line.

Forces are in pairs. A pair of forces exists acting on the two interacting objects. The size of the forces on the first object equals the size of the force on the second object. The direction of the force on the first object is opposite the direction of the force on the second object. Forces always come in pairs - equal and opposite action-reaction force pairs.

Speed in the Universe
How fast is Earth moving through space?

At Earth's midlatitudes -- including the United States -- the rate is about one thousand miles per hour. Faster at the equator and slower at the poles. Earth orbits the Sun at an average speed of 67,000 mph, or 18.5 miles a second. The entire solar system orbits the center of the Milky Way at 140 miles a second. Even at this great speed our solar system takes about 200 million yearsto orbit around our home galaxy.

Leonid meteoroids travel at 71 kilometers per second, more than 2,000 times the speed of a fast pitch in baseball. A meteor traveling that speed would travel around the Earth in less than 4 minutes.