The radian, denoted by the symbol, is the SI unit for measuring angles, and is the standard unit of angular measure used in many areas of mathematics. The length of an arc of a unit circle is numerically equal to the measurement in radians of the angle that it subtends; one radian is degrees or just under 57.3°

Molarity

It is one of the most widely used unit of concentration and is denoted by M. It is defined as no. of moles of solute present in 1 liter of solution. Thus,

Molarity = No. of moles of solute / Volume of solution(in Litres)

• According to Lenz’s law:-The polarity of the induced emf is such that it tends to produce induced current in such a direction that it opposes the change in magnetic flux that produced it.
• The (-) ive sign in given equatione= (-) (dΦ/dt)tells about the direction.

Format for Speech Writing - In order to write a perfect speech, we must be well acquainted with the topic and must possess a wide range of vocabulary, a thorough knowledge of the subject, some research, and excellent organizational skills. Here are the ideal format and tips to help you write your perfect speech.
A perfect speech must consist of:-

1. HEADING- The heading should be catchy and in not more than 5-6 words. You can go as creative as you want with this one just make sure you do not devote too much time to it in the exam.
2. OPENING LINE- This includes salutations, introduction, and the topic. Make sure you do not mention your personal details (name, school name, etc.).

Example- Respected Principal, teachers, and my dear friends! Today, I (the name is given in the question) stand before you all to speak on the topic “(given in the question)”.
OR you could start with a quote related to the topic and then go with the salutations and introduction.

1.  BODY- It is the main part of your writing piece.
2. It is always prescribed that you begin with a short introduction on the topic, it’s meant to be precise. 
3. Then you need to explain the current situation, the problems (if any), and whether after any corrective actions, betterment in the situation has been observed or not.
4. It may include advantages/ disadvantages depending upon the topic in question.
5. Now here, it is important you follow a sequence. It is possible that you have too many points or very few points. When you have a lot of varied points, it is better you choose a few best ones and write a line on each. In case you have very few already, explain them in at least two lines each.
6. You have to strictly follow the prescribed word limit in a limited time frame so just do not go on writing and writing.
7. MOST IMPORTANT- Always begin with your strongest point. You can accommodate the weaker ones in between and end with another strong point.
8. Feel free to give your personal opinion in one or two lines.
9. It is very important that you do not deviate from the topic. There are chances you may get ideas linking from one to another that may deviate you from the main point. You have to refrain from doing so.
10. SOLUTION/CONCLUDING PARAGRAPH- Now, it is to be remembered that wherever you elaborate a problem, you always have to mention the steps being taken to improvise the situation and suggest a few solutions as well.

Now, it would be great if you could add a few quotes relating to motivating the people to take action.
Here also, the rule of STRONG-WEAK-STRONG applies.

Answer:

If there is decrease in acceleration, it is called retardation. This means, rate of decrease in velocity is called retardation.A positive sign of the magnitude of acceleration shows increase in velocity and a negative sign show decrease in velocity.

Parallax is the displacement or the change in the apparent position of the object when viewed from two different points of view. The two points of view have their own line of sights and parallax is measured as half of the angle between the two lines of sights.

When you are traveling in a vehicle and you look around as you are moving, you will see that objects in the distances appear to move more slowly than the objects closer to you. This is the effect of parallax. Nearby objects have a larger parallax than the distant objects, so the parallax can be used to determine distances.

The phenomenon of parallax, when combined with triangulation, will yield the location of the object with considerable accuracy. Astronomers regularly use the parallax method to measure the distances of the closer stars.

Luminous intensity, the quantity of visible light that is emitted in unit time per unit solid angle. The unit for the quantity of light flowing from a source in any one second (the luminous power, or luminous flux) is called the lumen. The intensity is defined as power per unit area, and power is defined as energy per unit time. Thus: I=PA=EΔt1A. Because when intensity of incident light increases, it means that number of photons increases in incident light. If number of incident photons increases, then number of emitted photo electrons also increases, consequently the photo electric current increases.

Angular displacement is defined as “the angle in radians (degrees, revolutions) through which a point or line has been rotated in a specified sense about a specified axis”. It is the angle of the movement of a body in a circular path. Angular displacement is measured in units of radians. Two pi radians equals 360 degrees. The angular displacement is not a length (not measured in meters or feet), so an angular displacement is different than a linear displacement.

The motion of a rigid body which takes place in such a way that all of its particles move in circles about an axis with a common angular velocity; also, the rotation of a particle about a fixed point in space. Rotation around a fixed axis or about a fixed axis of revolution or motion with respect to a fixed axis of rotation is a special case of rotational motion. The fixed-axis hypothesis excludes the possibility of an axis changing its orientation and cannot describe such phenomena as wobbling or precession.

A unit is an internationally accepted standard for measurements of quantities.

• Measurement consists of a numeric quantity along with a relevant unit.
• Units for Fundamental or base quantities (like length, time etc.) are called Fundamental units.
• Units which are combination of fundamental units are called Derived units.
• Fundamental and Derived units together form a System of Units.

Angular velocity= w= 60rev/min
1 revolution= 2pi radian
one minute = 60 sec
w= 60*2pi/60
w= 2pi radian/sec
mass= 18g = 0.018 kg
distance =r= 8 cm = 0.08 m
f= mv^2/r
v=rw v^2=r^2w^2
f= mr^2w^2/r
r in division will be removed by removing square

F= mrw^2
f= 0.018*0.08*(2pi)^2
square of 2 is 4
nd pi^2= 9.87 as per your question
so:
0.018*0.08*4*9.87
= 0.05685
= 0.057

Frame of Reference

In order to know the change in position of an object, a reference point is required. Point O in the figure is the reference point or Origin and together with three axes, this system is called the coordinate system. A coordinate system with time frame is called frame of reference.

• Objects changing positions with time with respect to the frame of reference are in motion while those which do not change position are at rest.
• For a moving car, for the frame of reference outside the car, it appears moving. While for the frame of reference inside the car, the car appears stationary.

Angle of Friction beween any two surface in contact is defined as the angle which the resultant

of the force of limiting friction F_lim and normal reaction N makes with the direction of normal reaction N

as shown in figure. It is marked in the figure as θ.

The value of angle of friction depends on the material and nature of surfaces in contact. 

It can be seen from figure, tanθ = AC/OA = F_lim / N = μ , where μ is coefficient of limiting friction

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The angle of repose or angle of sliding  α is defined as the minimum angle of inclination of a plane

with the horizontal such that a body placed on the plane just begins to slide down.

Its value depends on the material and nature of the surface in contact. 

from the figure it can be seen that, f =mg sinα ...............(1)
N = mg cosα ....................(2)

hence we get,  f / N = tan α = μ  

Q u e s t i o n : What is the maximum possible resultant of two forces 2N and 1N.

A n s w e r ; 3N

3 N is the maximum  possible resultant of two forces 2 N and 1 N.

Distance traveled in n th second is given by:
Sn​=u+1/2a(2n−1)

Let 'u' be the initial velocity and 'a' be the uniform acceleration of the body.