The answer is D because when the positive charged side touches the negative charged side it nullifys part of the positively charged side, basically subtraction from my understanding?
Answer:
B) A stack of books is carried at waist level across a room
Explanation:
Work is defined as:
where
F is the force applied
d is the displacement of the object
is the angle between the direction of the force and of the displacement
From the formula, we see that the work done is zero when the force and the displacement are perpendicular to each other. Let's now analyze each situation:
A) A bookcase is slid across carpeting. --> work is done, because the force that pushes the bookcase is in the same direction of the displacement
B) A stack of books is carried at waist level across a room. --> no work is done, because the force to carry the book is vertical, while the displacement of the books is horizontal
C) A chair is lifted vertically with respect to the floor. --> work is done, because the force that lifts the chair is vertical, and the displacement is vertical as well
D) A table is dropped onto the ground. --> work is done, because the force of gravity (that makes the table falling down) is vertical and the displacement of the table is also vertical.
Answer:
The Forces of Flight
At any given time, there are four forces acting upon an aircraft.
These forces are lift, weight (or gravity), drag and thrust. Lift is
the key aerodynamic force that keeps objects in the air. It is the
force that opposes weight; thus, lift helps to keep an aircraft in
the air. Weight is the force that works vertically by pulling all
objects, including aircraft, toward the center of the Earth. In order
to fly an aircraft, something (lift) needs to press it in the opposite
direction of gravity. The weight of an object controls how strong
the pressure (lift) will need to be. Lift is that pressure. Drag is a
mechanical force generated by the interaction and contract of a
solid body, such as an airplane, with a fluid (liquid or gas). Finally,
the thrust is the force that is generated by the engines of an
aircraft in order for the aircraft to move forward.
Explanation:
Answer:
Unmeltedd ice = 308.109 g
Explanation:
Gibbs Free energy:
A systems Gibbs Free Energy is defined as the free energy of the product of the absolute temperature and the entropy change less than the enthalpy change.
Therefore, G = ΔH-TΔS
where G is Gibbs Free Energy
ΔH is enthalpy change
T is absolute temperature
ΔS is entropy change
Here since there is a phase change, therefore G will be 0.
∴ΔH = TΔS
Given: Temperature, T = 0°C = 273 K
Entropy change,ΔS = 600 J/K
Latent heat of fusion of water = 333 J/g
∴ΔH = TΔS
∴ΔH = 273 x 600
= 163800 J
So this is the amount of enthalpy that will be used into melting of ice.
∴ΔH = mass of ice melted x latent heat of fusion of water
Mass of ice melted = ΔH / latent heat of fusion of water
= 163800 / 333
= 491.891 g
This is the mass of ice melted.
And initial amount of ice is 800 g
Amount of ice left after melting = Initial amount of ice - amount of ice melted
= 800-491.891
= 308.109 g
Amount of ice remained after melting = 308.109 g
Question:
The water molecules now in your body were once part of a molecular cloud. Only about onemillionth of the mass of a molecular cloud is in the form of water molecules, and the mass density of such a cloud is roughly 2.0×10−21 g/cm^3.
Estimate the volume of a piece of molecular cloud that has the same amount of water as your body.
Answer:
The volume of cloud that has the same density as the amount of water in our body is 1.4×10²⁵ cm³
Explanation:
Here, we have mass density of cloud = 2.0×10⁻²¹ g/cm^3
Density = Mass/Volume
Volume = Mass/Density = If the mass is 40 kg and the body is made up of 70% by mass of water, we have
28 kg water = 28000 g
Therefore the Volume = 28 kg/ 2.0×10⁻²¹ g/cm^3 = 1.4×10¹⁹ m³ = 1.4×10²⁵ cm³.
Therefore, the volume of cloud that has the same density as the amount of water in our body = 1.4×10²⁵ cm³.
