why it is said that "a iron ball and a feather fall with same velocity in vacuum"?

Answer 1

because their acceleration due to gravity is independent of their mass

Answer 2

It is not just said, it is proved. In Fact one of the astronauts of Apollo tried it out on the moon and surely enough both the iron ball and the feather reached the ground at the same time.

It's very simple. Every physical body will move if it experiences a force. That force will accelerate it, causing it to move with increasing speed. The force on both the iron ball and the feather on Earth is due to gravity which is a constant value, so both accelerate in the same way. However on Earth there is air. This air will prevent the objects from falling (air resistance) according to the surface area (in fact, it's the ratio of surface area to volume!) of the object. As the feather has a greater surface area, air resistance is stronger on it than on the iron bal and the net accelerating force (gravity-air resistance) is lower than that for the iron ball, causing it to fall more slowly and reach the ground after the iron ball. On the moon or in any place where there is a gravity and there is no air, both will accelerate in the same way and both will reach the ground at the same time.To be more precise if both accelerate the same way their velocities will be equal at all times.

Answer 3

Because it's true. Without the air to reduce the acceleration of the feather, it falls just the same as an iron ball. In the atmosphere, the iron ball accelerates at a greater rate than the feather because it is denser and presents less air resistance than does the feather, which has a large surface area and low mass.

Answer 4

Gravity acts on all objects regardless of mass with the same acceleration: 32 ft/sec squared. In a vacuum there is no air resistance to slow the acceleration of the feather, so you will see that any 2 objects regardless of mass will be accelerated by gravity and achieve the same velocity when dropped simultaneously from the same height.

Answer 5

The acceleration due to gravity is taken to be a constant for all bodies.
If u are asking this doubt after doing gravitation, then the answers is this:
The earth pulls every objeat with the same acc. of gravity.

The earth's mass is very high when compared to iron balls and feathers. These are extremely tiny things and when compared to earths mass these have masses equal to zero nearly. So their pull of the earth is nearly zero.

Answer 6

It was proven on one of the moon shots. They took an eagle feather and a hammer.
What is going on is that wind resistance on earth slow the feather down. It was found that if wind resistance is not a factor then all objects fell to the ground at the same accelertion. The reason why was shown through newtons theories on gravitational acceleration.

Gravitational force of a falling object= its mass times acceleration. (moXao)

Gravity is moXmass of earth(me)*k/r^2

moXa=moXmeXk/r^2

the mo cancles out and you have;

a=meXk/r^2

Answer 7

because there is no air