Answer:
800
cm²
Explanation:
Given parameters:
radius of the coin = 20cm
Unknown:
Surface area of the coin = ?
Solution:
A coin is made up of two faces;
Surface area = 2(πr²)
Insert the parameters and solve;
Surface area = 2(
)
Surface area = 800cm²
E, there is no state of matter that has no particle motion, however a solid's particles are only vibrating.
The answer would be C: Rheostat. :)
Answer:
B. the force of friction of the road on the tires
Explanation:
Unless the car engine is like jet engine, the main force that accelerates the car forward is the force of friction of the road on the tires, which is ultimately driven by the force of engine on the tires shaft. As the engine, and the shaft are part of the system, their interaction is internal. According to Newton laws of motion, the acceleration needs external force, in this case it's the friction of the road on the tires.
