Effect Of Air Resistance Research Articles

The Effect of Air Resistance on Falling Balls

An experiment suitable for use in undergraduate physics courses is described to measure the effect of air resistance on falling balls. The results are in good agreement with those predicted by a theory with a resistive force depending on the square of the velocity.

Oxygen intake in track and treadmill running with observations on the effect of air resistance.

1. The relation of V(O2) and speed was measured on seven athletes running on a cinder track and an all-weather track. The results were compared with similar observations on four athletes running on a treadmill.2. In treadmill running the relation was linear and the zero intercept coincided with resting V(O2).3. In track running the relation was curvilinear, but was adequately represented by a linear regression over a range of speeds extending from 8.0 km/hr (2.2 m/sec) to 21.5 km/hr (6.0 m/sec). The slope of this line was substantially steeper than the regression line slope for treadmill running.4. The influence of air resistance in running was estimated from measurements of V(O2) on a subject running on a treadmill at constant speed against wind of varying velocity.5. The extra O(2) intake (DeltaV(O2)) associated with wind increased as the square of wind velocity. If wind velocity and running velocity are equal, as in running on a track in calm air, DeltaV(O2) will increase as the cube of velocity.6. It was estimated that the energy cost of overcoming air resistance in track running is about 8% of total energy cost at 21.5 km/hr (5000 m races) and 16% for sprinting 100 m in 10.0 sec.

Physics and games

Many interesting physical problems are posed by events which occur during the playing of various ball games, and the literature on the subject, though scanty, includes such well-known names as Coriolis, Rayleigh and J. J. Thomson. A few of the many problems which arise are here discussed. In a great number of games the player is concerned with the flight of a ball through the air and consequently with the effects of air resistance.

The Study of High Speed Rolling Friction : 1st Report, The Method of Measurement and Fundamental

In order to analyse the operating characteristics of rolling bearings, it is necessary to confirm the rolling friction at high speed. But the attempts for the sake of measuring the rolling friction have hitherto been done at low speed. In the experiment reported in this paper, using the raceway of outer ring of ball bearing as the track of planetary motion of ball, we have rotated a steel ball along this track at a high speed and have computed the rolling friction by measuring the variation of rotating speed. Moreover, by rotating the raceway at various speeds and making various kinds of the relative motion between raceway and steel ball, we have been able to eliminate the effect of air resistance and have clarified the rolling speed performance and load performance. As the special features of rolling friction at high speed, it have been revealed that the rolling friction increases with the increase of rolling speed and the rolling friction increases under the existence of a little oil.

The fallacy in physics

The first example cited by Dr. Maude in his interesting article on The fallacy in physics and mathematics in the December, 1958, Bulletin, recalls a difficulty which has perplexed me at intervals since the first artificial satellite was launched. Can any reader provide a satisfactory physical explanation of the mechanism whereby the effect of air resistance on such a satellite is to increase its velocity through the air ? It is easy to see why the effect occurs, but not so easy to see how it occurs. Presumably similar difficulties occur if one inquires too closely into the orbital velocities of electrons on the Bohr model, but we have become accustomed to accepting only mathematical explanations of phenomena on this scale.

Scale Height of the Upper Atmosphere

SEVERAL formulae have been published recently for calculating the effect of air resistance on orbits of artificial Earth satellites. The latest and most complete are by King-Hele and Leslie1. Nearly all these formulae are valid over a somewhat limited range of eccentricity and are based on a spherical Earth. The effect of ellipticity is by no means negligible and can be corrected for without much additional complication.