Classes
Class 9Class 10First YearSecond Year
$1 Whether true or false If false correct the following:a. Every body in the universe repels every other body with a force which is inversely proportional to the product of their masses.b. The force of gravitational attraction is directly proporti. onal to the square of the distance between two bodies.c. The force with which the earth-repels a body on Its surface towards its centre is equal to its weight.d. The value of \mathrm{g} increases with the increase of thz di tance of the body from the centre of earth.e. Gravitational force is of a very large order of about 6.67 \times 10^{-11} \mathrm{Nm}^{2} / \mathrm{kg}^{2} .f. If the cable carrying the elevator breaks the elevator will go up with an acceleration equal to g .$

$6. At what distance from the centre of the earth does the gravitational acceleration have one half the value that It has on the earths surface?$

$2. A hoop and disc have same mass and radius. Their rotational K.E are related by an equation.a) K . E_{\text {hoop }}=K . E_{\text {disc }} b) K . E_{\text {hoop }}=2 K . E_{\text {disc }} c) K . E_{\text {hoop }}=1 / 2 K . E_{\text {disc }} d) K . E_{\text {hoop }}=4 K . E_{\text {disc }}$

$23. A cyclist cycling around a circular racing track skids becausea) The centripetal force upon him is less than limiting frictionb) The centripetal force upon him is greater than limiting frictionc) The centripetal force upon him is equal to the limiting frictiond) The friction between the tyres of the cycle and road vanishes$

$45. The value of gravitational constant was determined bya) Newtonb) Keplerc) Cavendishd) Maxwell$

$5. Radius of geo-stationary orbit form center of earth is nearly.a) 42000 \mathrm{~km} b) 36000 \mathrm{~km} c) 24000 \mathrm{~km} d) 18000 \mathrm{~km}$

$40. The sun exerts a forces of attraction on the planets for keeping them in theira) Axesb) Spin-motionc) Orbitsd) None of them$