Question

Revision worksheet
class 9th
periodic Test 2
subject science
1Describe the new value of acceleration due to gravity when we go at( h )distance above from the Earth surface.
2.Drive the new value of acceleration due to gravity when we go distance (d) downwards inside the earth.
3. Define
* universal law of gravitation *true fall
* mass and weight.
4. Drive the formula for acceleration due to gravity under truefall.
5. A stone is dropped from the height of 50m.
(a) calculate the speed of the stone when it hits the ground (b)calculate the time taken by the stone to fall through this height.
6. If the total time taken by the stone to come on the ground level is 10 second, find the maximum height reached by the stone.
7.If the mass of both the object is tripled and distance between them is halved calculate the new force of gravitation.plese help me​

Answer 1

3.

(a) universal law of gravitation

Newton’s Law of Universal Gravitation states

that every particle attracts every other particle in the universe with a force that is directly proportional to the product of the masses and inversely proportional to the square of the distance between them

(B) mass and weight

The mass of an object is a measure of the object's inertial property, or the amount of matter it contains. The weight of an object is a measure of the force exerted on the object by gravity, or the force needed to support it.

(c)Free Fall

whenever object fall toward the earth under this alone, we say that the object are in free fall.