To simulate the Solar System, $3$ planets are chosen, they are Mercury,

Earth and Mars. You can set the initial condition like this: planets start at their

collinear Perihelia on the same side of the Sun. The directions of their initial

velocities are perpendicular to the collinear line, while Sun always stays still. You

can find their linear velocity in the table below. The mass of the Sun is $\backslash$geocircle $=$

$1\mathrm{.}9891\backslash$times $10$ kg$.$ Ignore the gravity between the planets.

Plot the orbits of Mercury, Earth and Mars in a $2$D figure. Calculate the orbital

period from your modelling and compare with the data in the table below.