# Lab Report 1.docx - Lawrence Timothy PHYS 1410-NV1 Mengying...

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Lawrence Timothy PHYS 1410-NV1 Mengying Shi Motion in Free-Fall 1 June 2016 Edidiong Etim -The motion of a body falling freely under gravitational force will be examined. -From the measured rate at which the velocity (v) changes with time (t), the acceleration (a) due to gravity (g) will be determined.
Introduction Have we ever wondered why objects fall when we release them? It is important to study free fall as it occurs frequently in our everyday lives. By conducting an experiment then finding out the acceleration due to gravity, we can determine the Earth’s gravitational field strength. One example for the importance of determining the Earth’s gravitational field strength remains true to all astrophysicists. Astrophysicists can set the Earth’s gravitational field strength as a benchmark when determining gravitational field strength of other planets in space. Hence, they will be able to compare gravitational field strengths of different planets with the Earth’s to conduct safe space expeditions. We have learned from Newton’s Second Law of motion that when there is a net force acting on a body, the body will accelerated by that force. Newton’s Second Law ΣF = ma Where: m = mass of the body a = acceleration ΣF = sum of forces When we release a body from rest, it falls due to the force acting on the body. This force points towards the center of the Earth and is called the “Weight”. The weight of an object is determined by the product of the mass of the object and the acceleration due to gravity. F g = mg Where: m = mass of the body a = acceleration due to gravity F g = Weight An accelerating body will undergo a change in velocity. Since air resistance can be neglected for experiments carried out at distances that are very much smaller than the Earth’s radius, the acceleration of the body will remain constant. For bodies moving with constant acceleration, the acceleration can be determined by the following Kinematic Equation. This will be called “Equation I”. As the acceleration of the body is constant, the graph of velocity against time will be a linear function. The value of the slope is the value of the acceleration due to gravity. a = v – u t or v = u + at Where: a = acceleration v = terminal velocity u = initial velocity t = time interval Since the body is moving with constant acceleration, the average velocity of the body can be determined by the displacement of the body over the time interval.
´ v = s t This will be “Equation II” Where: s = displacement of the body t = time interval ´ v = average velocity