Answer:

Explanation:
Density is defined as mass ler unit volume, expressed as

Where m is mass,
is density and v is the volume. For a sphere, volume is given as

Replacing this into the formula of density then

Given diameter of 2.24 in then the radius is 1.12 in. Substituting 0.82 lb for m then

Answer: Electric current originates from positively charged protons negatively charged electrons of an atom.
Explanation:
The movement of ions (positive or negative) from one point to another is called electric current.
An atom has three sub-atomic particles. These are protons, neutrons and electrons.
Protons are positively charged, neutrons have no charge and electrons are negatively charged. Protons and neutrons reside inside the nucleus of an atom whereas electrons revolve around the nucleus.
So, protons and electrons are responsible for originating electric current form an atom as these are the charged particles.
Thus, we can conclude that electric current originates from positively charged protons negatively charged electrons of an atom.
Explanation:
Specific cutting energy:
It the ratio of power required to cut the material to metal removal rate of material.If we take the force required to cut the material is F and velocity of cutting tool is V then cutting power will be the product of force and the cutting tool velocity.
Power P = F x V
Lets take the metal removal rate =MRR
Then the specific energy will be

If we consider that metal removal rate and cutting tool velocity is constant then when we increases the cutting force then specific energy will also increase.
Answer: b)Its ability to penetrate skin quickly due to its very small diameter
Explanation: Carbon nano tubes(CNT) are the material widely used in the medical field due to the atomic structure of it ans also have small size. Toxicity in the carbon nano tubes is because their small sized atomic particles which can enter the skin by penetration or inhalation. But are still preferred in the medicine because having unique properties like mechanical property, chemical property,surface property etc.