A1 Free Fall - EXPERIMENT FREE FALL Introduction: 1. Free...

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EXPERIMENT FREE FALL Introduction: 1. Free fall For uniform acceleration “ a ” (constant in magnitude and direction), the well-known kinematic equations of motion can be written as : v = v o + a t y y o = ½ (v o + v) t y y o = v o t + ½ a t 2 v 2 = v o 2 + 2 a (y y o ) where y , v , and a are the distance, instantaneous velocity and instantaneous acceleration, respectively. The initial conditions are: at t = 0, y = y o and v = v o . Whenever the air resistance on a falling object is negligible, the motion is referred to as free fall . Near the earth’s surface, the acceleration due to gravity “g” is nearly constant over the range of motion and approximately equals 9.80 m/s 2 downward. This value decreases with increasing altitude and slightly varies with latitude. A freely falling object moves freely under the effect of gravity regardless of its initial condition. For a freely falling body, the same kinematic equations, mentioned above, hold true with the substitution a = g . 2. Projectile motion If a projectile is projected horizontally, it describes an arc as shown in Fig.(1). The horizontal distance traveled by the projectile x is called the “range” . The vertical distance of the falling projectile is y . The initial conditions of the motion are: at t = 0, the horizontal component of the velocity is v xo and the vertical component v yo = 0 . The acceleration is uniform i.e. constant and downward and has the value g , the acceleration due to gravity. From the kinematic equations of motion, we can get the equation of the path: v yo =0 v xo y = g x 2 / 2 v xo 2 x The path is a parabola with its vertex at y distance v x the original point where the object starts of its motion .This equation relates (1) the fall v y v acceleration due to gravity g , (2) the range x , (3) the distance of fall y , and Range, x (4) the initial velocity v xo . y Fig.(1) Range and fall of a projectile
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Exercise 1: The equation of motion for a body free-falling from rest can be expressed as y = ½ g t 2 , where y is the distance the object has traveled from its starting point, g is the acceleration due to gravity, and t is the time elapsed since the motion began. In this experiment, you will find an estimate to g by carefully timing the fall of a steel ball from various heights. Setup and Operation: y Dowel Pin (Press here) Release Plate Thumbscrew Contact screw Receptor Pad Fig. (2) Equipment Setup 9 V DC Adaptor To the Ball Release Mechanism Receptor Pad Time To 120 VAC, 60 Hz or 220/240 VAC, 50 Hz (1) Clamp the ball release mechanism to a lab stand, or any other device that will hold it vertical and at the desired height over the floor or table, as shown in figure 2. For best results, the drop height y should be 1.5 – 2.0 m. Shorter heights will work fine, but accuracy is reduced proportionally. (2)
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A1 Free Fall - EXPERIMENT FREE FALL Introduction: 1. Free...

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