Dynamic Digital Measurement of the Impact Process Dynamic digital measurement of the impact process combines the force sensor and modern digital measuring technology in achieving the digital measurement of the dynamic impulsive force during impact event.It is both a basic training apparatus and a very general-purpose instrument with many practical applications.Force sensors,charge amplifier as well as transient data acquisition system can be widely used in general mechanical measurement,shock and vibration researches. Experimental Objective 1.Leam the principle and how to use the air track.Learn the principle of the light blocking board,photoelectric timer,instantaneous speed measurement mechanism,and the use of digital millisecond meter. 2.Get the physical picture of how the impact force varies with time during a collision process, deepening the understanding of basic concepts like momentum,collision and impulse. 3.Get some basic knowledge of modem sensor technology including the piezoelectric effect, sensing mechanism,and signal modulation. 4.Understand the characteristics and advantages of current digital technology through the transient signal recording and its conversion to actual physical constants. 5.Develop the ability to use computers for data processing by writing simple programs. Experimental Principle Collision and impact processes are usually instantaneous processes.Object momentum change before and after a collision subjects to the law of momentum: mv-mo =fF(t)di (1) Traditional air track apparatus can not be used for the experimental verification of the law of momentum due to the difficulty in carrying out dynamical measurement of the impact force.This current system uses a piezoelectric force sensor to convert the force signal instantaneously into an electric signal and output it as a voltage signal after charge amplification. As long as we can measure the output voltagev(t)from the charge amplifier,we know the evolution ofthe impact force as function of timeF(). v(t)=GSF(t) GS is the conversion factor. Impact waveform obtained in the experiment nomally assumes a half-sine shape as shown in the figure.In order to better understand how to obtain the instantaneous impulse,we listed in the following one sample measurement and the corresponding data analysis procedures. Momentum measurement: Slider block with light blocking bar spacing AL=1.000cmDynamic Digital Measurement of the Impact Process Dynamic digital measurement of the impact process combines the force sensor and modern digital measuring technology in achieving the digital measurement of the dynamic impulsive force during impact event. It is both a basic training apparatus and a very general-purpose instrument with many practical applications. Force sensors, charge amplifier as well as transient data acquisition system can be widely used in general mechanical measurement, shock and vibration researches. Experimental Objective 1. Learn the principle and how to use the air track. Learn the principle of the light blocking board, photoelectric timer, instantaneous speed measurement mechanism, and the use of digital millisecond meter. 2. Get the physical picture of how the impact force varies with time during a collision process, deepening the understanding of basic concepts like momentum, collision and impulse. 3. Get some basic knowledge of modern sensor technology including the piezoelectric effect, sensing mechanism, and signal modulation. 4. Understand the characteristics and advantages of current digital technology through the transient signal recording and its conversion to actual physical constants. 5. Develop the ability to use computers for data processing by writing simple programs. Experimental Principle Collision and impact processes are usually instantaneous processes. Object momentum change before and after a collision subjectsto the law of momentum:  − = t mv mv F t dt 0 0 ( ) (1) Traditional air track apparatus can not be used for the experimental verification of the law of momentum due to the difficulty in carrying out dynamical measurement of the impact force. This current system uses a piezoelectric force sensor to convert the force signal instantaneously into an electric signal and output it as a voltage signal after charge amplification. As long as we can measure the output voltage from the charge amplifier, we know the evolution of the impact force as function of time 。 v t GS F t ( ) = 0 ( ) is the conversion factor. Impact waveform obtained in the experiment normally assumes a half-sine shape as shown in the figure. In order to better understand how to obtain the instantaneous impulse, we listed in the following one sample measurement and the corresponding data analysis procedures. Momentum measurement : Slider block with light blocking bar spacing ΔL = 1.000cm v t( ) F t( ) GS0