Why does an object released from the hand , fall on the earth ?

Why does an object fall down ?

The figure shows the speed as a function of time for an object in free fall near the surface of the earth. The object was dropped from rest in a long evacuated cylinder . If the same object were released in air, the magnitude of its acceleration would begin at the free-fall value, but it would decrease continuously is zero as the object continued to fall. For which one of the choices given does the solid line best represent the speed of the object as a function of time when it is dropped from rest in air ? Note: The dashed line shows the free-fall under vacuum graph for comparison.

If a traveller releases an object from her hand in the spacecraft,what will happen?

Weightlessness in space: Space travellers as well as objects in the spacecraft appear to be floating. Why does this happen? Though the spacecradft is at a height from the surface of the earth the value of g there is not zero. In the space station the value of g is only 11% less than its value on the surface of the earth. Thus, the height of a spacecraft is not the reason for their weightlessness. Their weightlessness is caused by their being in the state of free fall. Though the spacecraft is not falling on the earth because of its velocity along the orbit, the only force acting on it is the gravitational force of the earth and therefore it is in a free fall state. As the velocity of free fall does not depend on the properties of an object, the velocity of free falls is the same for the spacecraft, the travellers and the objects in the craft. Thus, if a traveller releases an object from her hand, it will remain stationary with respect to her and will appear to be weightless. If a traveller releases an object from her hand in the spacecraft, what will happen?

The earth is continuously pulling the Moon towards its centre. Why the moon does not fall on to the earth?

The earth is continuously pulling the Moon towards its centre. Why the moon does not fall on to the earth?