Gravitation

Question 1

Value of G?

Answer 1

6.67×10^-11 Nm/kg^2

Question 2

Formula for Gravitational force?

Answer 2

F=Gm1m2/r^2

Question 3

Value of cos 180°?

Answer 3

-1

Question 4

Integration of sin theta?

Answer 4

-Cos theta

Question 5

Formula for Gravitational field?

Answer 5

E =F / m

Question 6

Gravitational field due to a point mass ‘ M’?( F)

Answer 6

E=-GM/r^2

Question 7

What is the field at the center of symmetrical mass distribution?

Answer 7

Zero

Question 8

Formula for Gravitational field due to a circular ring at any angle ¢ ?

Answer 8

E=GM/R^2¢ 2sin¢/2

Question 9

Gravitational field due to a hollow sphere at r>R ?

Answer 9

E=GM/r^2

Question 10

Gravitational field due to a hollow sphere at r=R ?

Answer 10

E=GM/R^2 (constant)

Question 11

Gravitational field due to a solid sphere at r>R?

Answer 11

E=GM/r^2

Question 12

Gravitational field due to a solid sphere at r=R?

Answer 12

E=GM/R^2

Question 13

Gravitational field at any point inside a uniform solid sphere ?

Answer 13

E=4G(rho)πr/3

or

E=GMr/R^3 ( E directly proportional to r)

Question 14

Relation between Gravitational force and field?

Answer 14

F=mE

Question 15

Gravitational potential energy for a single mass?

Answer 15

U=0

Question 16

Uf–Ui=?

Answer 16

Uf–Ui= –W ( by Gravitational force )

Question 17

U configuration= ?

Answer 17

U configuration = –W ( by Gravitational force in bringing each mass from infinity)
= +W ( by ext. force)

U configuration= –Gm1m2/r

Question 18

Gravitational potential energy at infinity?

Answer 18

0

ZERO

Question 19

Gravitational potential energy is a scalar or vector quantity?

Answer 19

Scalar

( can be added directly)

Question 20

nCr=?

Answer 20

nCr= n!/r!(n–r)!

( !=factorial)
(n=no of masses -for eg)
(r=no of pairs - for eg)

Eg- 4C2= 4!/2!2!
=4×3×2×1/2×1×2×1

Question 21

Length of Diagonal of a square?

Answer 21

a√2