Question

. A mass m is placed at point P lies on the axis of a
ring of mass M and radius R at a distance R from its
centre. The gravitational force on mass m is
(a)GMm/√2R²
(b)GMm/2R²
(c) GMm/2√2R²
(d) GMm/4R²​

Answer 1

Answer:

Explanation:

GMm2–√R2

GMm2R2

GMm22–√R2

GMm4R2

Answer :

C

Solution :

( c) The situation is as shown in the figure. Gravitational force on an object of mass m at point P distance d from centre O lying on the axis of the circular ring of radius R and mass M is given by

F=GMmd(R2+d2)3/2

When d=R, then

F=GMmR(R2+R2)3/2=GMmR(2R2)3/2=GMmR23/2R3=GMm22–√R2