Lab 8 Newton's Law of Gravity Purpose: To study Newton's law of gravity and determine the value of the |ravitational constant. In 1687 Sir [saac law of gravitation. Newton hypothesized the It states: Every mass exerts 2 force of attraction on every other mass. The strength of this force 15 directly proportional to the product of their masses and mversely proportional separation. MMathematicall to the square of their Ly: The strength of the force is directly proportional to the product of their masses: F ooy mg 1 @ my The strength of the force is inversely proportional to the square of the distance between them. Where F is the strength of the force (or simply force), m and m- are the masses of the two objects involved and r is the distance between them, and o represents proportionality. Equation (1) and (2) can be combined to get: F=6 = rz Where *G' iz a constant called gravitational constant. [n metric units, the value of G i3 G=667x10" Nm'kg' In this experiment we will verify (1) and (2) and using (3) we will determine the value of *G". You must review the specific details of Newton's law of gravity from the textbook before starting fowork on this lab. You can use your textbook. Experimental Procedure: Go to the URL: http:/'phet colorado.edu/en/simulation/gravity-force-lab Click on the simulation to start the experiment. Please play around with the simulation and make vourself famliar with it. Part 1: Variation of force with mass In this part we will look at the varistion of force with masses at a fixed distance. Choose a distance between the red and the blue balls. I would recommend a distance betwezen 5 and 6 meters. Distance between the balls is the distance between the centers of mass of the balls. See the picture below. To change the distance between the objects, you can click and drag the balls left znd right. To measure distance, place the mler as shown in the picture. Force on m2 by m1 = 0,000 000 004 386 N - Force on m1 by m2 = 0,000 000 004 366 N 4 Center of mass T T T T T T Tood 23 8 9 10 Loveiliaauliaesl TN Change mass [ " Mass1 Mass 2 ] & Show vaiuos | A ww |[ Al smw |[p] 1 . 10 : 0 + Write down the distance between the balle (r) below. Once you choose a distance, vou won't change it until you move to part 2 of the experiment. * Choose values for Mass 1 (m) and Mass 2 (m). I would recommend that you choose masses which are at least 25 kg, Write them down in the tzble below. Also record the force (F) for these two mzsses. The force 15 displayed at the top of the simulation It says 'Force onm2 by m1\" or 'Force on ml by m2'. The two values are the same. Choose two new values for Mass 1 and Mass 2. For both Mass 1 and Mass 2, you can change mass by clicking repeatedly on the left or the right amow-head a5 shown in the Part 3: Determination of gravitational constant In this part we will determine gravitational constant. Equation (3) is an equation of a straight line when force (F) is plotted against my mar with a slope equal to gravitational constant. So we will find force for different values of m, mar and plot our data. . Find 'F' for the following suggested values of my, ma and r. Please note that you will vary all three variables (mi, ma, and r). The values provided are only suggested You are free to choose your own values. If you choose different values, make sure to change them in the table accordingly. Record 'F' in the right most column mi (kg) ma (kg) r (m) 50 F (N) 90 6.5 40 70 60 6 100 100 4 75 53 95 91 7.2 25 72 3.6 18 2.8