Newton theorized that the apple would experience the accelerating effect of the force of gravity no matter how far from the Earth the apple was. He expanded this idea to all objects near the Earth. What was Newton's explanation for why the moon doesn't crash to the Earth due to gravitational force? Do we use this principle for any application today? Give an example, if so.

The moon also falls towards the Earth, but having a tangential speed, the acceleration it has is used in the change of direction of its speed,

Explanation:

Newton explained that all objects attract each other, as the Earth is much greater than the apple, it is this that falls towards the Earth.

The moon also falls towards the Earth, but having a tangential speed, the acceleration it has is used in the change of direction of its speed, in general this acceleration is called centripetal

This principle is used in all circular motion devices, for example the merry-go-round in parks, the radius of the circle is proportional to the speed of the turn and therefore to the centripetal acceleration of the device.

the old price per ounce is c/4.

the new price per ounce is c/3.6.

the ratio of the old price to the new one is

(c/4)/(c/3.6) = (c/c)×(3.6/4) = 0.9 . . = 9/10 . . "nine tenths" in either form