EXPERIMENT 2 FREE FALL MOTION L Objective To verify the value of acceleration due to gravity using free fall motion. II. Conceptual Background In air, a coin falls faster than a piece of paper. However, in vacuum, they fall at the same rate as may be demonstrated by the 'coin and feather' experiment placed inside a vacuum tube. If air resistance is negligible, a body falls freely under gravity with uniform acceleration. This is called acceleration due to gravity denoted by g. The standard value of g is 9.8 m/s?. The equations of motion for uniformly accelerated motion can be applied to falling objects. Instead of a, acceleration due to gravity, -g (negative g) is substituted in the kinematics equations. Thus, the equations become y = vat - 1/2 gt? v/ = vol - 2gy Vr = Vo - gt where y is the vertical displacement, wy and v. are the final and initial velocities respectively and f is the time of fall, between initial and final positions. III. Materials Metal ball Piece of stone Digital timer Meterstick IV. Procedure 1. Go up on the last floor of the Laboratory building in your school. 2. Measure the height by dropping one end of a long cord until it reaches the ground. 3. Determine the length of the cord. This is the height of fall. Weigh the first object, the metal ball. 5. Drop the metal ball and record the time it takes the ball to reach the ground. 176. Compute for the value of acceleration due to gravity using the equations for free fall motion. 7. Make ten trials 8. Record your data. 9. Repeat steps 2 to 6 this time using the second object, piece of stone. 10. Compute the percentage error for the acceleration due to gravity. V. Data and Results A. Metal ball mass of the metal ball grams Trial y (m) t (sec) g (m/se]) Average Percentage Error % B. Piece of stone mass of the piece of stone = grams Trial y (m) (sec) g (m/se) Average Percentage Error %VI. Computations VIL. Conclusions VIII. Questions and Problems 1. Compare the time of fall and the computed acceleration due to gravity obtained using different masses, a metal ball and a piece of stone, from the experiment. What accounts for their difference or similarity? 2. Sketch the acceleration-time graph of the motion of the metal ball and the piece of stone. What do these graphs suggest