The Virtual Laboratory: Experiment ___ Projectile Motion This is the instruction set for Projectile Motion Virtual Experiment. It must be used with the experiment's computer simulation. Introduction In this experiment, we will investigate some properties of projectile motion. The basic physics is simple: a ball rolls down an incline which has been placed on top of a table. When it reaches the bottom of the incline, it proceeds to roll off the edge of the table and falls "freely" solely under the influence of gravity. This motion is two-dimensional. If we refer to the horizontal direction as the x-direction and the vertical direction as the y-direction, we have two independent position equations of motion for the ball upon its leaving the table: In these equations, is the ball's (constant, horizontal) velocity as it leaves the table and g is the acceleration due to gravity. At the surface of the Earth, g is a constant . In order for these equations to make sense, you will have to determine where the origin of the coordinate system is for the simulation. In this experiment, you will record "experimental" data that will enable you to calculate a value for the acceleration due to gravity, g and compare it to the known value given in the previous paragraph. Experimental Procedure The experimental procedure is as follows: 1. Click the Start button. The ball will be moved to position A if it is not already there. 2. When the ball hits the ground (that is when the simulation stops), click the Mark button. The ball's position (in centimeters) when it hit the ground will be marked by a red dot. 3. Use the ruler slide marker to determine the x-coordinate of this position and record it in the Distance Table below. Record the time interval indicated by the Photogate Timer in the Time Interval Table. 4. Click the Reset button. The ball will return to its starting point and the timer will reset. 5. Repeat steps 1-4 three more times to obtain four (4) trials. 6. After the last Reset, click on the Next button. The ball will now move to position B on the incline. Repeat steps 1-4 to obtain four (4) trials from this starting position. 7. Repeat the above sequence, moving the ball to positions C, D and E. Diameter of the ball (m): 0.04_ Height of the Table (m): 1.50_ Distance Table Start Position (incline) (cm) (cm) (cm) (cm) A B C D E Time Interval Table Start Position (incline) (ms) (ms) (ms) (ms) A B C D E Calculations Open the Excel spreadsheet for this experiment or use the Tables provided in excel. For each start position, enter the position and time interval data into the spreadsheet. NOTE: the time intervals are in milliseconds (ms) and you must convert to seconds (s). For each start position, average the four recorded distances and enter the result in the last column. NOTE: the position data are in centimeters (cm) and you must convert to meters (m). For each start position, average the four recorded time intervals and enter in the column. Use the average time interval and the ball's diameter to calculate the velocity v0