+ Gravity: O on O off O Gravity Force Velocity - Path Grid Star Mass 0.5 Our Sun 1.5 2.0 Planet Mass 0.5 Earth 1.5 2.0 Fast Normal 141 Do 393 Earth Days Clear Slow+ 3 Gravity: O on off Gravity Force Velocity - Path Grid Star Mass 0.5 Our Sun 1.5 2.0 Planet Mass 0.5 Earth 1.5 2.0 0 O Fast 141 Earth Days Normal 141 Clear O Slow3 - Kepler's Laws Open the simulation (https://phet.colorado.edu/en/simulation/gravity-and-orbits). Choose Model. Select the Sun and Earth system on the top of right corner. Select path, grid and velocity to display the data. + Gravity: O on . off O Gravity Force O Velocity Path U Grid Star Mass 0.5 Our Sun 1.5 Planet Mass 0.5 Earth 1.5 2.0 Fast Forward 0 Earth Days Normal Clear Slow Motion Run the simulation. Be careful with your observations 14. Which is the shape of orbit? 15. How does the speed of the Earth depend on its distance to the Sun? 16. Does the orbit change if you change the mass of the Earth? 17. Does the orbit change if you change the mass of the Sun?The 'perihelion' is the point of the orbit where the planet is the closest to the star, the 'aphelion' instead is the farthest. Display also the Gravity Force. 18. How does the magnitude of the force change as the planet moves away from the perihelion? 19. What is the period of the Earth around the Sun? Kepler 3rd Law relates the period of revolution T of a planet orbiting the Sun (of mass M), with its semimajor axis a 2 _4.TE 3 2 TGMa Restart, and increase the Star Mass to 1.5. Use this setting to check your answers to the questions 15. Now by looking at the simulation: 20. What is the approximate value of the period now? 21. What is the approximate ratio of the aphelion over the perihelion? 22. Use Kepler 3rd Law to calculate the semi-major axis a + Gravity: O on off Gravity Force Velocity - Path Grid Star Mass 0.5 Our Sun 1.5 2.0 Planet Mass 0.5 Earth 1.5 2.0 0 O Fast 196 Earth Days Normal 141 Clear C SlowRestart, again Star Mass to 1.5 and display the velocity. Double the initial speed (you might have to zoom out: use vertical bar top left corner). Run the simulation. 24. What happens to the planet? 25. Is it possible to find an initial velocity (try both speed and direction) such that the planet will spiral inward toward the star and then crash on it