Gravitation

Question 12:Assume you are a scientist. Your group has found a new system of bodies. Th is system is made up of a star at the centre and five planets in a circular orbit around the star. Table 2 shows information on this system of bodies.(a) Calculate the gravitational acceleration, escape velocity and orbital period … Read more

Question 10:Figure 6 shows three bodies A, B and C. It is given that the gravitational force between A and B is P.State in terms of P, the gravitational force between (i) B and C (ii) A and C Answer:Between A and B : $$ \begin{aligned} F_{\mathrm{AB}} & =\frac{G m_1 m_2}{r^2} \\ P & =\frac{G … Read more

Question 7:Th e Earth orbits the Sun with radius of orbit of 1.50 × 1011 m and orbital period of 1 year. Radius of orbit of planet Saturn is 1.43 × 1012 m. What is the orbital period of Saturn? Answer:Orbital period of the Earth, 𝑇1=1.00 years, Orbital period of Satrn = 𝑇2Orbital radius of the … Read more

Question 5:(a) What are the factors that determine the value of the gravitational acceleration?(b) A satellite is at a distance of 4.20 × 107 m from the centre of the Earth.What is the value of the gravitational acceleration at this position? [Mass of the Earth = 5.97 × 1024 kg] Answer:(a)– Mass of the Earth– … Read more

Question 3:Figure 2 shows the orbit of planet Uranus.Describe the change in linear speed of planet Uranus when it moves from point A to point B. Answer:Keplers’ Second Law states that a line connecting a planet to the Sun sweep out equal areas in equal times.The shorter the distance of a planet from the Sun, … Read more

Question 1:Figure 1 shows planet Mars orbits the Sun in a circular motion with orbital period, T.(a) For planet Mars, write the formula for:(i) gravitational force in terms of m, M and r(ii) centripetal force in terms of m, v and r(iii) linear speed in terms of r and T(b) Derive an expression for the … Read more

Question 1:Compare and contrast geostationary and non-geostationary satellites. Answer: Question 2: What factors determine the linear speed of satellites orbiting the Earth? Answer:$$ \text { Linear speed of satellite, } v=\sqrt{\frac{G M}{r}} $$As GM is constant, linear speed of the satellite only depends on the radius of its orbit. If a satellite is at a height, … Read more

Question 1:State Kepler’s first law. Answer:Kepler’s first law states that all planets move in elliptical orbits with the Sun at one focus. Question 2:(a) State Kepler’s second law.(b) Figure 3.32 shows the orbit of a planet around the Sun. Compare the linear speed of the planet at positions X, Y and Z. Answer:(a) Kepler’s second … Read more

Question 4:A weather satellite orbits the Earth at a height of 560 km. What is the value of gravitational acceleration at the position of the satellite? [G = 6.67 × 10–11 N m2 kg–2, mass of the Earth = 5.97 × 1024 kg, radius of the Earth = 6.37 × 106 m] Answer:$$ \begin{aligned} h … Read more

Question 1:State Newton’s Universal Law of Gravitation. Answer:Newton’s Universal Law of Gravitation states that the gravitational force between two bodies is directly proportional to the product of the masses of both bodies and inversely proportional to the square of the distance between the centres of the two bodies. Question 2:State two factors which influence the … Read more