An unknown substance is tested and found to have the following physical properties: brittle fair conductor of electricity dull (not shiny) the substance is most likely a metal metalloid nonmetal cannot be determined without more data

Metalloid

Explanation:

Metals are good conductors of electricity and are generally shiny.

Metalloids are the elements of the periodic table that have properties of both metals and non metals. They may be shiny or dull. They are brittle and are fair conductors of electricity.

Non metals are dull, do not conduct electricity and brittle.

Hence the substance is most likely a metalloid.

more than, less

less than, more

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.