18. a) The materials that are in contact. The two materials and the nature of their surfaces. ...
b) The force pushing the two surfaces together. Pushing the surfaces together causes the more of the asperities to come together and increases the surface area in contact with each other.
19. the quantity of motion of a moving body, measured as a product of its mass and velocity.
20. According to Newton's third law of motion, action force is equal to reaction but acts on two different bodies and in opposite directions. When a horse pushes the ground, the ground reacts and exerts a force on the horse in the forward direction. This force is able to overcome friction force of the cart and it moves.
21. The mass of an object is a measure of the object's inertial property, or the amount of matter it contains. The weight of an object is a measure of the force exerted on the object by gravity, or the force needed to support it. The pull of gravity on the earth gives an object a downward acceleration of about 9.8 m/s2.
22. R12. Mass is more fundamental because it is an intrinsic property of an object. Weight varies with location depending upon the acceleration due to gravity eg. for a mass m = 10kg on Earth it`s weight is W = mg = 10 x 10 = 100N.
Answer:
acid rain
Explanation:
When sulfur dioxide combines with water and air, it forms sulfuric acid, which is the main component of acid rain. Acid rain can: cause deforestation.
Answer:
14.4g
Explanation:
First, we need to write a balanced equation for the reaction between Fe and O2 to produce Fe2O3. This is illustrated below:
4Fe + 3O2 —> 2Fe2O3
From the balanced equation,
4moles of Fe produced 2moles of Fe2O3.
Therefore, 0.18mol of Fe will produce = (0.18x2) /4 = 0.09mol of Fe2O3.
Now we need to find the mass present in 0.09mol of Fe2O3. This can be achieved by doing the following:
Molar Mass of Fe2O3 = (56x2) + (16x3) = 112 + 48 = 160g/mol
Number of mole of Fe2O3 = 0.09mol
Number of mole = Mass /Molar Mass
Mass = number of mole x molar Mass
Mass of Fe2O3 = 0.09 x 160 = 14.4g
Answer:
B. Similar fossils were found in different continents.
Hope this helps! chemical test is a qualitative or quantitative procedure designed to identify, quantify, or characterise a chemical compound or chemical group. It is used to see if the driver had presence of alcohol or drugs in their system
