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Lys), , 7, o, n, ~, =, =, a, N, o, ix, , , , , , YDS" (MED) sTupy, mEDY MATERIAL — 1 PUC PHYSICS (NCERT-Gravilation a, Gravitation ; nie 3 |, | Itis the force of attra, virtue of their masses., , , , n between any two bodies in the universe by, , , , Universal law, Statement, , , , , jon (Newton's Law of Gravitation), , , , The magni, ate eos of gravitational force of attraction between two, irect 4, Ms ¥ Proportional to the product of their masses and inversely, n :, Bice z ‘i Sduare of the distance between them. The direction acts, along the line joining the two bodies, , bo, , , , , Explanation, , , , Let m, & m, be the masses of two bodies separated by a distance d., Let F be the force of attraction between them., From Newton’s law of gravitation,, , mm, :, SS, & ?, , , , , , Fo, , , , Where G is the universal gravitational constant., , , , , , NOTE, in vector form, , , , , , is the unit vector in the direction of F,, , the distance between the bodies, ;, , , , Where, , , , are the masses of two bodies, a, , , , d, d, m, and m2, G_ is the universal gravitational constant., , , , ———

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), , z, bh, SS, =, a, q, ), i], , , , , , , , , , es nceny-crasttion, mcrvns: con) STUDY MATERIA 1 rc PHYSICS OO, Y, avitational constant (G) mee...), Se yeO =F |, ss Se i oan aca! | |, We have, F= 43 4, | tion Gravitat constant, al to the force of attraction | I, , , , , Gravitational constant is numerically equ!, kg and separated by 4 distance of, , 5 each of mass 1, , , , between the two bor, , Imetre., + ig called as universal gravitalionc® col, , , , Why gravitational constan', The value of G does not depend on, , 1) The nature and size of the bodies. :, the two bodies, , , , , , , , , 2) The nature of the medium between :, , 3) The physical conditions such os temperature pressure etc. of surroundi |, , medium. i |, + is called as universal gravitational constant. |, , There fore gravitational constant, , itation is called as universal law of gravitation., plicable for all bodies in the universe and, , , , f grer, , , , Newton’s law, , Newton’s law of gravitation is apy, hence it is called as universal law of gravitation., , , , , , SI unit of gravitational constant is Nm? kg”, lis dimensional formula is [|G] = [M'LT*], The scientist Cayendish determined the value of G experimentally in 1798, , Its value is given by G = 6.67 x 107! Nm? kg”, , The 4 os tare between two point masses .But it can be applied to, sized bodies by assuming the entire mas:, , a s of the body concentrated, 6. The gravitational force between two particles constitutes an action « |, r. As the value of G is small the force of attraction be, force becomes appreciable, onl |, , ne SS), , , , , , , , the bodies haye large masses., Ex: The gravitational force between thi, es i, keeps the earth in orbit around the nu aan ores "|, , 7. Among the basic forces in nature, th i, , the gravitational force is th, ie weakest., , It is a central force (9) It is mutual force

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LEGENDS’ (\, — (GDN) Srupy sy,, MATERIA, ies, , CHIIYSICS (NCERT)-Gn, , , , , vity ds, isthe force of attraction exert 6 na body, exe, , led by the earth ona, , eleration due to, , , , ive the relat, avitational con:, , , , , , inthe above figure,, Mis the mass of the earth, m is the mass of the body,, R is the radius of the eat, "Newton's law of gravitation, we have, GMm, , ace, , Fron, Fe, , , , s clear that the value of 9, ifferent masses are, , , , : rom the above equation it i, ihe body. There fore if two bodies of, yacuum (not i air) from the same he ight, they w reach the, srify this fact Newton evacuated a wide glass tube and relea:, feather of bird and found that, both reached the bott, called as coin and feather experiment of Newto!, sees are allowed to fall freely 19, , to effect. This causes different, , vd heavier body reaches the aro, , n the surface of any, Is vertically dow!, , , , , , , , , , , , , , , , , , , , , , , , ~ bodies of different masses @!, quation holds ©, , , , , , 3) The above e', , i) When a body is dropped from a height, it, , Tocceleration. It is same for all bodies respective of fl, , "composition. This ‘cceleration is due ' the gravitation, ‘acceleration is ca led acceleration due to gravity. His repre, , ne earth:, , , , e center of, , always directed towards thi, , , , , , , , , e acceleration :, 2 ee, duced in the motion of body di, of body due to gravity:, , , , is independent of 1, lowed to fall freely in the, , planet of radi, , heir shape, , re), , +, RK, a, ae, a, rs, =), N, , , , , , , , , , , he mass of, , ‘earth simultaneously. TO, sed a coin and a piece of, ‘om simultaneously. This, , , , the force of buoyancy j}, ations in the two}, th nearly uniform, size, mass oF, , of the earth This, Wis, , Jn., , accelert, \d earlier., ius R and mass M, , , , , , , , , , , mwvards, , , , al pul, ented by the letter o, , , , , , a

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NOTE, a = (1-28), his Vio, , Sund that the accsloration due to gravity, When h = &, 2 Sa Ht, celeration due to 2 then g,= 0., , Grayit, earth. This result oo, 70°° ot height equal to the hel of the, , — PProximate,, , Consider the SqUation,, , From above equotion, , is height increases,, , , , , , ie Expression for, , ae i, ce of the earth “*°!e*tion due to gravity at a point below, , , , , , , , , , , , is a point on the surface of the earth,, , is the point ata depth d from the surface of the earth,, , is the centre of earth,, , is the mass of the earth of radius R with respect to the point A., is the mass of shaded portion of the earth of radius (R-d) , vl, , ‘ation due to gravity at the point A, , f), GM, a, , Where G = universal gravitational constant., , , , ation due to gravity at the point B,, \, GM, => (2), Sa (Rd), , 2022/1/7 14:06