
Every object in the universe attracts every other object with a force which is proportional to the product of their masses and inversely proportional to the square of the distance between them. The forces along the line joining the centre of the two objects.
❍ Let us consider two masses m1 and m2 line at a separation distance d. Let the force of attraction between the two objects be F.
According to universal law of gravitation,

Also,

Combining both, We will get

Or, We can write it as,

Where, G is the constant of proportionality and it is called 'Universal Gravitational constant'.
☯️ Hence, derived !!
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Direction from A to B divided by time(30s)
A conductor is something which allows electricity to pass through it
an example is a coin
An insulator is something which cannot allow electricity to pass through it
an example is plastic (or plastic cotton reel, plastic container ect.)
Static electricity is when you rub two things together to create static
I'm not sure if i helped on the last question but i am definitely sure of the first ones
Speed of sound in cold air < Speed of sound in Warm air < Speed of sound in hot molten lead < Speed of sound in water
Explanation:
Step 1:
Speed of sound in water varies from 1450 to 1498 meters per second
Speed of sound in Hot Molten lead is approximately 1210 meters per second
Speed of sound in warm air is approximately 338.89 meters per second
Speed of sound in cold air is approximately 293.33 meters per second
Step 2:
In warm air sound travels faster than that of sound travelling nature in cold air.
∴ Speed of sound in cold air < Speed of sound in Warm air < Speed of sound in hot molten lead < Speed of sound in water
Speed of sound in cold air the slowest while Speed of sound in water is the fastest mean.