The Local Acceleration Due to Gravity as Determined with a Cart and Track

The aim of this lab is to determine an experimental value for the local acceleration due to gravity. In order to do this, a cart was released down a track and allowed to pass through two photogates recording the entrance and exit times of the cart. These times along with the length of a light blocking strip on the cart, were used to calculate the acceleration of the cart down the track at various angles, and through linearization, the experimental value for the local acceleration due to gravity was determined to be 10.027 ± 0.312 m/s2. This value has a percent error of only 2.2% from the accepted value of 9.8 m/s2, which proves that this method of determining local acceleration due to gravity can be effective and accurate. Additionally, this experimental value shows how similar the approximation is to the accepted value.

Measurement of Acceleration Due to Gravity Using Arduino and Ultrasonic Sensor

In this study, a simple Arduino-based experiment was designed to examine the acceleration of the object during free fall and to calculate the value of “g” (acceleration due to gravity). Experimental data on the free fall of a plastic box through the air was gathered with the help of an ultrasonic distance sensor (HC-SR04). Readings were taken at different intervals during the fall to obtain distance time curves. Acceleration during the free fall was then determined by applying the standard kinematic equations. The shape of the distance-time graphs obtained from the experimental setup was in good agreement with the predicted graphs and the calculated values of g lie within the expected range. After repeated experiments, value of gravitational acceleration was found to be 9.805 m/s2. Hardware and software prepared for the experiment are sufficient to examine movement of ordinary objects during free fall, therefore the experiment can be easily settled in a laboratory for the purpose of learning and teaching.

High Precision Absolute Gravity Meter Based on Time-to-Digital Conversion in FPGA

This paper proposes a novel method to design a high precision portable gravity acceleration meter on the Field Programmable Gate Array(FPGA)platform.Two technologies are used in FPGA to improve the time measurement accuracy to 54 ps and the measurement accuracy of g to the level of 1μGal(1 Gal=1 cm/s^(2)).The one is the proposed clock rising edge counting method for measuring the coarse time,in which the measured coarse time resolution can reach 5 ns by setting the clock frequency up to 200 MHz.The other is the realization of the time-to-digital conversion(TDC)circuits in FPGA which can further improve the time measurement accuracy to 54 ps.In the TDC circuit,we analyze the influence of the frequency stability of crystal oscillator and the distance of infrared tube on the measurement accuracy of g.The increase of frequency stability(10^(–9)to 10^(–11))can greatly improve the measurement accuracy of g(5.8143 to 2.0799μGal),but further increase of frequency stability(10^(–11)to 10^(–12))has little effect on improving the accuracy of g.Through analysis and simulation,it is found that the setting of distance between laser pair also has a great influence on the accuracy of g.Only when the distance is set to the optimal,we can make the accuracy of g the highest.In this paper,the method of obtaining the best distance and the corresponding accuracy of g are given.In addition,the proposed system uses Nios II soft core processor to implement all the controlling,calculation and display functions,which improves system integration,reduces system cost and meets the needs of field geological survey and gravity prospecting.