( iii) Law of period The square of the time period of revolution of planet around the sun is directly proportional to the cube semi-major axis of its elliptical orbit.
T 2 & infi; a 3 or( T1 / T2) 2 =( a1 / a2) 3 where, a = semi-major axis of the elliptical orbit.
Important Points
( i) A missile is launched with a velocity less than the escape velocity. The sum of its kinetic energy and potential energy is negative.
( ii) The orbital speed of jupiter is less than the orbital speed of earth.
( iii) A bomb explodes on the moon. You cannot hear the sound of the explosion on earth.
( iv) A bottle filled with water at 30 ° C and fitted with a cork is taken to the moon. If the cork is opened at the surface of the moon then water will boil.
( v) For a satellite orbiting near earth’ s surface( a) Orbital velocity = 8 km / s( b) Time period = 84 min approximately
( c) Angular speed ω = 2π / 84 rad / min = 0.00125 rad / s
( vi) Inertial mass and gravitational mass( a) Inertial mass = force / acceleration( b) Gravitational mass = weight of body / acceleration due to gravity( c) They are equal to each other in magnitude.
( d) Gravitational mass of a body is affected by the presence of other bodies near it. Inertial mass of a body remains unaffected by the presence of other bodies near it.