Solved MCQs | Chapter 5 Gravitation | Physics 9th | Balochistan Textbook Board Quetta | Urdu/Hindi

1. Encircle the correct option. Which of the following is the correct mathematical expression for Newton’s law of gravitation? (a) F=G (m_1 m_2)/2r (b) F=G (m_1 m_2)/r^2  (c) F=g (m_1 m_2)/r^2 (d) F=G (m_1 m_2)/r^3 If the distance between two masses is doubled, the gravitational attractive force between them will (a) be reduced to half (b) be reduced to a quarter (c) be doubled (d) become four times The unit of universal gravitational constant G is (a) Nm^(-2) 〖kg〗^(-2) (b) Nm^(-1) 〖kg〗^(-2) (c) Nm^2 〖kg〗^(-2)  (d) Nm〖kg〗^(-2) Which of the following is correct expression for mass of Earth? (a) M_E=(gR_E)/G (b) M_E=(GR_E)/g (c) M_E=(g〖R_E〗^2)/G  (d) M_E=G/(g〖R_E〗^2 ) The mass and radius of a planet are half that of corresponding Earth’s values. The acceleration due to gravity on this planet will be equal to (a) 1/2 g (b) g (c) 2g  (d) 4g What will be the value of g at an altitude of h=2R_E? (a) 2g (b) 3g (c) 1/2 g (d) 1/9 g  If ‘h’ represents the altitude of satellite of mass ‘m’ moving around Earth having mass M_E and radius R_E respectively then orbital velocity of the satellite is given by (a) v=(GM_E)/(R_E+h)^2 (b) v=(GM_E)/(R_E+h)^ (c) v=(G〖M_E〗^2)/(R_E+h)^ (d) v=√((GM_E)/(R_E+h)^ )  If v_1 and v_2 represent the orbital speeds of low and high altitude satellites then these speeds are related by (a) v_2=v_1 (b) v_2=〖v_1〗^2 (c) v_2 greater then v_1 (d) v_2 less then v_1 