Question

a body weighs 3.5 kg weight on the surface of earth what will be the it's weight on the surface of a planet whose mass is 1/7 th of the mass of the earth and radius half of that of the earth

Answer 1

Answer:

Mass of body on earth =3.5 kg

Weight of the body on earth W

E

=mg=m

R

E

2

GM

E

.

Where G=gravitational constant ,M= mass of Earth and R=radius of earth

Now weight of the body on the planet W

P

=mg

P

=m

R

P

2

GM

P

As mass remains constant we can equate for acceleration due to gravity of the planet

g

P

g

P

=

R

E

2

GM

E

R

P

2

GM

P

--------(A)

As mass of planet M

P

=

7

1

M

E

and radius of planet R

P

=

2

1

R

E

Putting the above values in A we get

g

E

g

P

=

R

E

2

GM

E

4

1

R

E

2

G

7

1

M

E

g

P

=

7

4

g

E

=

7

40

Now weight of the body on the planet W

P

=mg

W

P

=3.5×

7

40

=20N