Answer:
photosynthesis is the process by which green plant manufacture their own food using sunlight from the sun , water and mineral salt from the soil
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The main requirement for a good conductor of electricity is to have a lot of valence electrons. Valence electrons are the electrons of the outer shells of atoms not bound with other atoms (for example through covalent bounds). These electrons are "free to escape" as soon as an electric field with enough intensity is applied to the material, and therefore these electrons will be free to move in the material producing an electric current.
Answer:
F = 294.3 [N]
Explanation:
To solve this problem we must use Newton's second law which tells us that force is equal to the product of mass by acceleration. It is this particular case the acceleration is due to the gravitational acceleration since the body is in free fall.
Therefore we have:
F = m*g
where:
F = force [N]
m = mass = 30 [kg]
g = gravity acceleration = 9.81 [m/s^2]
F = 30*9.81
F = 294.3 [N]
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.