Lab 2 Linear Motion

Lab 2 Linear Motion: Measuring g Value Objectives When you have completed this assignment, you will be able to: 1. Understand the concept of linear constant acceleration motion. 2. Measure the acceleration of free-falling objects 3. Calculate the acceleration due to gravity, g. Discussion A freely falling object is an object moving freely under the influence of the gravitational force only. Regardless of its initial motion, the freely falling object experiences a downward acceleration. This acceleration is constant. The motion of a freely falling object is the motion in one dimension under constant acceleration, only this motion is along the vertical. If we choose down-ward as the positive direction of y (a y = g = 9.8 m/s 2 ), the following equations will describe the motion: Velocity as a function of time: v y = v yo + g∙t [1] Velocity as a function of displacement: v y 2 = v y 0 2 + 2 ∙gy [2] Displacement as a function of time: y = v y 0 ∙t + 1 2 g∙t 2 [3] Displacement as a function of velocity & time: y = ( v y 0 + v y 2 ) ∙t [4] Equipment Computer with internet Procedures: Go to and open the Projectile Motion simulation. When it asks which section option you want to use, choose “ Intro .” Notice the following  the cannon (sitting on top left) can change its vertical height relative to the ground by dragging it up and down  the cannon ball angle can be changed by dragging and turning the cannon pipe.  the initial speed can be changed through the sliding bar on the bottom left.  different objects can be shot from the cannon, by selecting the object in the menu bar located top right.

 there are measuring equipment, such as a tape measure and the Time/Range/Height (TRH) device in the tool box next to the menu bar. Part I: Measuring Acceleration  Change the object/projectile to a golf ball (menu bar on top right)  sliding the initial speed to 0 m/s,  drag the cannon pipe and rotating to angle to -90° (straight down)  drag the cannon height to 4 m.  Record the golf ball’s mass and diameter in the data table 1.  Fire the golf ball by clicking on the fire button  Use the Time/Range/Height measuring equipment (TRH) to measure the time following the steps:  Use your mouse to drag the TRH out of the tool box into the large, blue area in the center of the window.  After clicking on the red “launch” button, notice the vertical path/trajectory line.  Place the TRH crosshairs at the end of the path and record the time of fall in table 1.  Repeat the steps for each of the height in table 1 by dragging the cannon up. Data Table 1 Mass of golf ball: [0.05] kg Diameter of golf ball: [0.04] m Height, h (m) Time, t (s) t 2 g = (2h)/t 2 4 m [0.09] [0.81] [9.88] 6 m 1.11 1.23 9.74 8 m 1.28 1.64 9.77 10 m 1.43 2.05 9.76 12 m 1.56 2.43 9.88 15 m 1.75 3.06 9.80