Answer:
d. The earth rotates around the sun
Explanation:
- Nicolas Copernicus is considered the first person to give the theory of heliocentric, or Sun-centered system of our planetary system.
- In the heliocentric system, it is considered that the sun is stationary and the earth revolves around the sun.
- He stated that the sun is at the center of the universe and the earth spins on its axis once daily and revolves around the sun in one year.
- And today we know it is correct that earth rotates on its own axis and also revolves around the sun.
Answer:
Efficiency is the percent of work put into a machine by the user (input work) that becomes work done by the machine (output work).
Explanation:
It is a measure of how well a machine reduces friction.
