If the body moves with acceleration, then it is influenced surely by a certain force. For it it is also a draft layer of time at present. In the real world even if the body moves evenly and rectilinearly, force of draft has to overcome resistance forces. This force can be found through equally effective all forces which affect a body. In the equipment determine draft force, knowing the power and speed of a body.
It is required to you
- - dynamometer;
- - accelerometer;
- - speedometer or the radar for measurement of speed;
- - calculator.
Instruction
1. To measure draft force, attach a dynamometer to a body and begin to move evenly it on a surface. The dynamometer will show force of draft which needs to be put to a body that it moved evenly. You make change in Newtons.
2. If the body of the known weight moves on a plain surface, force of draft can be calculated. For this purpose define friction coefficient between a surface on which the body, and a body μ moves. It can be done according to the special table. Define how the body moves. If evenly, then find force of draft of F, having increased friction coefficient by the body weight of m and acceleration of gravity of g=10 of m/s² (F=μ ∙ m∙g).
3. For example, if the car weighing 1200 kg moves on the horizontal road evenly, at coefficient of friction 0.05, then force of draft of its engine will be F=0,05∙1200∙10=600 H. If higher precision of measurement is necessary, take m/s g=9.81².
4. In case the body has acceleration under the influence of draft force, it will be equal to F=m ∙ (μ ∙ to g+a). Where an is value of acceleration, in m/s² which can be measured by the accelerometer.
5. To measure force of draft of the engine, determine its maximum power. It, as a rule, is given in technical documentation to it. Accelerate the device which is set by this engine in motion to the maximum speed, observing all precautionary measures. Measure speed by a speedometer or the special radar. To find the maximum force of draft of engine F, divide its power in N watts, into v speed in m/s (F=N/v).
6. For example, if the maximum engine capacity of the car of 96 kW, (if power is given in horsepowers, increase this value by 735 to receive it in watts), and its maximum speed of 216 km/h, what maximum force of draft of the engine? Find power in watts: 96∙1000=96000 watts. Express speed in m/s, for this purpose 216∙1000/3600=60 m/s. Determine force of draft of the engine: F=960000/60=1600 N.