Answer: 
Explanation:
Centripetal acceleration
is calculated by the following equation:
Where:
is the Earth's orbital speed
is the orbital radius

The answer is A.) igneous rocks
Answer: Mabye like an ocean with dolphins swiming/jumping? Or even use the blue as a sky and then put green grass and do foxes or and a phoenix flying with a fox under it?
Explanation:
Just some ideas!
Answer: a = 4 m/s²
Explanation:
a = Δv/t = (30 - 18) / 3 = 4 m/s²