can someone help me with this question and show all working so i can understand please

Q1a)

Over the years, some researchers have tried to make connections between the planetary alignment of Jupiter and Saturn in relation to our Sun, and the occurrence of earthquakes on our planet. The theory behind this research is that the force of the gravitational pull of both Jupiter and Saturn combined, is enough to overcome the pull from the Sun and therefore cause small perturbations in the Earth's crust, thus, causing earthquakes. Prove to yourself that this area of research is not worth pursuing by calculating the magnitude of the net gravitational force on Earth due to both Jupiter and Saturn being on one side of the Earth and having the Sun perpendicular to this alignment (see figure below, not drawn to scale). Earth Jupiter Sun Satur To calculate the net gravitational force for this question, use the following values: Mass of Earth = 5.972 x 1024 kg Mass of Jupiter = 1.898 x 10* kg Mass of Saturn = 5.683 x 1025 kg Mass of Sun = 1.989 x 10" kg Distance from Earth to Jupiter = 6.283 x 10ll m Distance from Earth to Saturn = 1.047 x 10 2 m Distance from Earth to Sun = 1.496 x 101 m G = 6.674 x 10-1 m3/s2. kg Give your answer to 4 significant figures.Before the days of quartz clocks, pendulums were used to keep time. A grandfather clock has a physical pendulum consisting of a long thin rod and a solid disc attached to the end of it. For a grandfather clock to keep correct time, each swing (from one side to the other, i.e., half the period of oscillation) must count out a time of 1 s. A particular setup of a grandfather clock has a rod length of 90 cm that has a mass of 400 g, and an attached disc of radius 15 cm and a mass of 1.0 kg. Determine swing time of the pendulum for this clock. Ignore the number of significant figures given in the question and give your answer to 7 significant figures