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:
B
Explanation:
The gravity accelleration values are the same for both planets.
Explanation:
Since liquid isopropanol is a polar liquid and water is also a polar solvent. So, when both of them are added together then according to the like dissolves like principle they get dissolved.
At the molecular level, the polar molecules of isopropanol get attracted towards the polar molecules of water at the surface of water.
As a result, water molecules get surrounded by isopropanol. Thus, water molecules enter the solution and evenly spread into the solution.
Answer: 226 Subscript 88 Baseline Upper R a right arrow Superscript 222 Subscript 86 Baseline Upper R n + Superscript 4 Subscript 2 Baseline Upper H e
Explanation:
Alpha decay : When a larger nuclei decays into smaller nuclei by releasing alpha particle. In this process, the mass number and atomic number is reduced by 4 and 2 units respectively.
The general representation of alpha decay reaction is:
Representation of Radium decays to form Radon
Thus 226 Subscript 88 Baseline Upper R a right arrow Superscript 222 Subscript 86 Baseline Upper R n + Superscript 4 Subscript 2 Baseline Upper H e represents alpha decay.
Answer:
Explanation:
Matter is anything that has weight and occupies space.
To prove that a bicycle is a matter, we need to show that it has weight and will occupy space.
When you put the bicycle on a weighing scale, you will see the weight of the bicycle. This a proof that bicycle is a matter.
To show that the bicycle can occupy space, place the device in a tank full of water. From the tank, the bicycle will displace some water. Substances that cannot occupy space will not behave in such manner.
