The sun is the centre of our solar system
Answer:
The force of attraction between the molecules of the same substance
Explanation:
Normal force for the rock because that makes an object stable at its position.
static friction because micro-welts hold its particle on its position so it doesn't change in position by a potential energy. Gravity makes it stay on the ground because its force attraction between an object and the earth.
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the polluted urban environment affects the health and quality of life
Kinetic energy = mass time squared speed divided by 2
W=mv^2/2 = 50*10*10/2 = 2500 J