A non-membranous cell organelle is ribosome. Ribosomes are extremely small, round bodies found either in the free state in the cytoplasm or attached to the surface of the ER.They are composed of ribonucleoproteic (ribonucleic acid and protein) .The main function of ribosomes is to act as a platform for the synthesis of proteins.

The second law of motion states that the rate of change of momentum of an object is proportional to the applied unbalanced force in the direction of force.

The  quantity  of  motion  in  a  body depends  on  the product of mass  and  velocity  of  the  body termed as momentum.

The momentum (p) of a body is defined as the product of its mass (m) and velocity (v) and has the same direction as that of the velocity. Its SI unit is kilogram metre per second (kg m s−¹).

Momentum = mass × velocity

p = m × v

Momentum has both magnitude as well as direction; hence it is a vector quantity.

Momentum of a body at rest is zero.

Assertion: The momentum (p) of a body is defined as the product of its mass (m) and velocity (v) and has the same direction as that of the velocity.

Reason: Its SI unit is kilogram metre per second (kg m s−¹).

Both A and R are true and R is the correct explanation of assertion.

Both A and R are true but R is not the correct explanation of assertion.

A is true but R is false.

A is false but R is true.

• Mathematical Formulation of Second Law of Motion:

Suppose an object of mass, m is moving along a straight line with an initial velocity, u. It is uniformly accelerated to velocity, v in time, t by the application of a constant force, F throughout the time, t. The initial and final momentum of the object will be, p1 = mu and p2 = mv respectively.

The change in momentum ∝ p2 – p1

∝ mv – mu

∝ m × (v – u).

The rate of change of momentum ∝ m × (v – u)/t

Or, the applied force,

F ∝ m × (v – u)/t

F = km × (v – u)/t

= kma

Here, a = [(v – u)/t ] is the acceleration, which is the rate of change of velocity. The quantity, k is a constant of proportionality.

The SI unit of mass and acceleration are kg and ms-2.

One unit of force is defined as the amount that produces an acceleration of 1 ms-2  in an object of 1 kg mass.

1 unit of force = k × (1 kg) × (1 ms-2).

The unit of force is kg ms-2 or newton, which has the symbol N. The second law of motion gives us a method to measure the force acting on an object as a product of its mass and acceleration.

Isotopes are variants of a particular element with different a different number of neutrons. For example, the two isotopes of Uranium are, ²³⁵₉₂ U and ²³⁹₉₂ U. 

Isobars are elements that have the same number of nucleons (sum of protons and neutrons). The series of elements with 40 Mass number serves as a good example; ⁴⁰₁₆S, ⁴⁰₁₇Cl, ⁴⁰₁₈Ar, ⁴⁰₁₉K, and ⁴⁰₂₀Ca. 

Isotones are atoms that have the same neutron number but different proton number. For example, ³⁶₁₆S, ³⁷₁₇Cl, ³⁸₁₈Ar, ³⁹₁₉K and ⁴⁰₂₀Ca are all isotones of 20 since they all contain 20 neutrons.

The Cell theory says that the cells form the fundamental structural and functional units of all living organisms; proposed in 1838 by Matthias Schleiden and by Theodor Schwann.

The mass per unit volume of a substance is called density (density = mass/volume). As the volume of a substance increases, its density decreases.

Liquids have a lower density than that of solids. Water is also a liquid so it should also have less density than that of solid that is ice.

Though ice is solid, it has a cage-like structure hence there are a large number of empty spaces between its particles. These spaces are larger as compared to the spaces present between the particles of water. Thus for a given mass of water, the volume of ice is greater than that of water. Hence, the density of ice is less than that of water. A substance with lower density than water can float on water. Therefore, ice floats on water.

J. E. Purkinje in the year 1839 coined the term 'protoplasm' for the fluid substance of the cell.

Tincture of iodine is an antiseptic which is used for cleaning the cuts. It is also known as iodine tincture or as weak iodine solution. The composition of tincture of iodine is 2-7% of elemental iodine and rest with either potassium iodide or sodium iodide.

The solvent is alcohol and water while the solute is iodine.

The process by which cells or parts of an organism change during development to serve a specific function. The cells of an animal in its early embryonic phase, for example, are identical at first but develop by differentiation into specific tissues, such as bone, heart muscle, and skin. Differentiation in (developmental biology) refers to the normal process by which a less specialized cell undergoes maturation to become more distinct in form and function. It is also called cell differentiation.

1. Liquids which do not mix with each other and form separate layers are called immiscible liquids.

2. They are separated by using separating funnel.

In physics, a charged particle is a particle with an electric charge. It may be an ion, such as a molecule or atom with a surplus or deficit of electrons relative to protons. An atom is a small particle (piece) of matter. It is made up of even smaller particles called protons, which carry a positive (+) electrical charge; neutrons, which have no charge; and electrons, which have a negative (-) charge.

• The new substances produced as a result of chemical reaction are called products.
• The method of representing a chemical reaction with the help of symbols and formulae of substances involved in it is called a chemical equation.
• A balanced chemical equation has an equal number of atoms of different elements in the reactants and products.
• An unbalanced chemical equation has unequal number of atoms of one or more elements in the reactants and products.
• Those reactions in which two or more substances combine to form a single substance is called a combination reaction.
• Those reactions in which a compound splits up into two or more simpler substances is called a decomposition reaction.
• Those reactions in which one element takes the place of another element in a compound, are known as displacement reactions.
• Those reactions in which two compounds react by an exchange of ions to form two new compounds are called double displacement reactions.
• Reactions which involve the addition of oxygen or the removal of hydrogen are called oxidation reactions.

• Prokaryotes are the organisms, that lack membrane-bound organelles while eukaryotes have these organelles. 
• ER is a eukaryotic organelle with a network of tubules, vesicles, and cisternae within the cells.
• Ribosomes are the nonmembrane bound organelles and are found in both prokaryotes and eukaryotes. 
• DNA is the genetic material present in both prokaryotes and eukaryotes.

Evaporation is the process in which a liquid state of matter (water)  is converted into a gaseous state of matter (vapor).

Examples of evaporation:

• Crystallization
• Drying of clothes

Following are the factors that affect the evaporation:

• Temperature: As the temperature increases, the rate of evaporation also increases. Temperature and rate of evaporation are proportional to each other
• Surface area: As the surface area increases, the rate of evaporation increases. The surface area and rate of evaporation are proportional to each other.
• Humidity: The rate of evaporation decreases with an increase in humidity. Humidity and the rate of evaporation are inversely proportional to each other.
• Wind speed: Increase in wind speed results in increased evaporation. Wind speed and rate of evaporation are proportional to each other.

• A molecule is a collection of various atoms that combine chemically with each other.

• These atoms are bound together by certain forces of attraction.

• Atoms of the same elements or different elements can bind together to form molecules.

Speed = 90km/h = 25m/s
Distance = 25m
0-625 = 50a
a = -12.5m/s²
0 = 25 - 12.5t
t = 250/125 = 4sec

The slope of a velocity graph represents the acceleration of the object. So, the value of the slope at a particular time represents the acceleration of the object at that instant. The slope of a velocity-time graph is acceleration. The slope of a linear function. The steepness of a hill is called a slope. The same goes for the steepness of a line. The slope is defined as the ratio of the vertical change between two points, the rise, to the horizontal change between the same two points, the run. If the acceleration is positive, then the line is an upward sloping line (i.e., the slope is positive). If the acceleration is negative, then the velocity-time graph is a downward sloping line (i.e., the slope is negative).

The physical state of water at its boiling point temperature of 100 degree Celsius will be both liquid state as well as gaseous state. This is because at its boiling point of 100 degree celsius the liquid state of water starts changing into its Gaseous state (steam). At 0°C, solid-state. We know that the freezing point of water is 0 °C. The liquid form of water starts to become solid (ice) at this temperature. Water is unique because the properties of water allow it to exist in all three states of matter! Water is usually a liquid, but when it reaches to 32° Fahrenheit (F), it freezes into ice. (Ice is the solid state of water.)

The shortest distance measured from the initial to the final position of an object is known as the displacement.

For motion of the object from O to A, the distance covered is 60 km and the magnitude of displacement is also 60 km. During its motion from O to A and back to B, the distance covered = 60 km + 25 km = 85 km while the magnitude of displacement = 35 km.

Thus, the magnitude of displacement (35 km) is not equal to the path length (85 km). If we consider the object to travel back to O, the final position concides with the initial position, and therefore, the displacement is zero. However, the distance covered in this journey is OA + AO = 60 km + 60 km = 120 km. Thus, two different physical quantities — the distance and the displacement, are used to describe the overall motion of an object and to locate its final position with reference to its initial position at a given time.

Activity:

1. Take some ammonium chloride. Crush it and put it in a china dish.

2. Put an inverted funnel over the china dish.

3. Put a cotton plug on the stem of the funnel, as shown in the diagram below.

4. Now, heat the china dish slowly with the help of a Bunsen burner and observe.

5. Ammonium chloride which is in the solid state on exposure to heat will directly change into the vapour state.

6. The vapours on rising up in the funnel will start condensing and form crystals of ammonium chloride.