Find weight of a man on his planet if his weight on earth is 65kg ,provided that :
Mass of planet = 16(Mass of earth)
Radius of planet = 2(Radius of earth)
Thank you
Answers
Answer:
Any two objects that have mass attract each other with a force we call gravity. You
probably never noticed this for small objects, because the force is so weak. But the Earth
has lots of mass, and so it exerts a big gravitational force on you. We call that force your
weight. The fact that gravity is actually a force of attraction is not obvious. Prior to the
work of Isaac Newton, it was assumed that gravity was simply the natural tendency of
objects to move downward.
If you weigh 150 lb, and are sitting about 1 meter (3.3 feet) from another person of
similar weight, then the gravitational force of attraction between the two of you is 10-7
lb.
This seems small, but such forces can be measured; it is about the same as the weight of a
flea.
You weigh less when you stand on the Moon, because the force of attraction is less. If
you weigh 150 lb on the Earth, you would weigh only 25 lb on the Moon. You haven’t
changed (you are made up of the same atoms), but the force exerted on you is different.
Physicists like to say that your mass hasn’t changed, only your weight. Think of mass as
the amount of material, and weight as the force of attraction of the Earth (or whatever
other planet or satellite you are standing on).
Mass is commonly measured in kilograms. If you put a kilogram of material on the
surface of the Earth, the pull of gravity will be a force of 2.2 lbs. So a good definition of
a kilogram is an amount of material that weighs 2.2 lbs when placed on the surface of the
Earth. That number is worth remembering.1
Go to the surface of Jupiter, and you will
weigh nearly 400 lbs. On the surface of the Sun you will weigh about 2 tons, at least for
the brief moment before you are fried to a crisp. But in all cases your mass will be 68 kg.
The equation that describes the pull of gravity between two objects was discovered by
Isaac Newton. It says that the force of attraction is proportional to the mass – double the
mass and the force doubles. The force also depends on the distance. It is an inverse
square law. It is inverse because when the distance gets larger, the force gets smaller. It
is a square law because if you triple the distance, the force decreases by nine; if you make
the distance increase by 4, then the force goes down by 16, etc