For determination of force of resistance of air create conditions under which the body will begin to move by gravity evenly and rectilinearly. Calculate value of gravity, it will be equal to air resistance force. If the body moves in air, gathering speed, force of its resistance is by means of Newton's laws, also force of resistance of air can be found from conservation law of mechanical energy and special aerodynamic formulas.
It is required to you
- range finder, scales, speedometer or radar, ruler, stop watch.
Instruction
1. Determination of resistance of air to evenly falling body Measure body weight by means of scales. Having dumped it from some height, achieve that it moved evenly. Increase body weight in kilograms by acceleration of gravity, (9.81 m/s²), the gravity operating on a body will be result. And as it moves evenly and rectilinearly, gravity will be equal to air resistance force.
2. Determination of resistance of air to the body gathering you skorostyopredelit body weight by means of scales. After the body began to move, by means of a speedometer or the radar measure its instantaneous initial velocity. At the end of the site measure its instantaneous final velocity. Measure speeds in meters per second. If devices measure it in kilometers per hour, divide value into 3.6. In parallel with the help of a stop watch define time for which there was this change. Having taken away initial from final speed and having divided result for a while, find acceleration with which the body moves. Then find force which forces a body to change speed. If the body falls, then it is gravity if the body moves horizontally – force of draft of the engine. From this force take away the work of body weight on its acceleration (Fc=F+m•a). It will also be air resistance force. It is important that at the movement the body did not touch the earth, for example, moved on the airbag or fell down.
3. Determination of resistance of air to the body falling with a vysotyizmerta body weight also dump it from height which is in advance known. At contact with the Earth's surface record body speed by means of a speedometer or the radar. After that find the work of the acceleration of gravity of 9.81 m/s² on height from which the body fell, take away the speed squared from this value. Increase the received result by body weight and divide into height from which it fell (Fc=m • (9.81•H-v²) / H). It will also be air resistance force.