Wind
Wind is the moving air and is caused by differences in air pressure within our atmosphere. This note has information about the wind and the causes for its occurrence.
Summary
Wind is the moving air and is caused by differences in air pressure within our atmosphere. This note has information about the wind and the causes for its occurrence.
Things to Remember
- Moving air is called wind.
- Wind is caused by differences in air pressure within our atmosphere.
- The hurricane occurring near the coastal areas is very powerful.
- We should not go to the areas where hurricane is occurring.
MCQs
No MCQs found.
Subjective Questions
Q1:
If A = {2,4,6,8,10} and B = {4,8,10,12,14}, find A∪B.
Type: Very_short Difficulty: Easy
Q2:
If A = {2,4,6,8,10} and B = {4,8,10,12,14}, find A∩B.
Type: Very_short Difficulty: Easy
Q3:
If A = {2,4,6,8,10} and B = {4,8,10,12,14}, find A-B.
Type: Short Difficulty: Easy
Q4:
If A = {2,4,6,8,10} and B = {4,8,10,12,14}, find B-A
Type: Short Difficulty: Easy
<p>B-A</p>
<p>= {x: x ∈ A and x ∉ A}</p>
<p>= {4,8,10,12,14} - {2,4,6,8,10}</p>
<p>= {12,14}</p>
Q5:
If A = {2,4,6,8,10} and B = {4,8,10,12,14}, find (A-B)∪(B-A).
Type: Very_short Difficulty: Easy
Q6:
If n(A) = 30, n(B) = 40, n(A∩B) = 15 and n(\(\overline{A∪B}\)) = 10,find n(A∪B) and n(∪). Also,show these information in a venn diagram.
Type: Long Difficulty: Easy
<p>Here,</p>
<p>n(A)=30, n(B)=40, n(A∩B)=15 and n(\(\overline{A∪B}\))=10</p>
<p>We have, n(A∪B) = n(A) + n(B)-n(A∩B) = 30+40-15 = 55</p>
<p>n(∪) = n(A∪B)+n(\(\overline{A∪B}\)) = 55+10 = 65</p>
<p>Then, n(A∩B)=15, write 15 in the portion common to both A and B.</p>
<p>Also, n(A-B) = n(A) - n(A∩B)</p>
<p>=30-15= 15, write 15 in the portion represented by horizontal lines.</p>
<p>Again, n(B-A)=n(B) - n(A∩B)</p>
<p>=40-15=25, write 25 in the portion represented by vertical lines.</p>
<figure class="inline-left" style="width: 386px;"><img src="/uploads/ex_1.png" alt="." width="232" height="205" />
<figcaption></figcaption>
</figure>
Q7:
In a class of 60 students,30 students take part in games,32 take part in dances and 7 take part in none of these two.
- How many take part in the both game?
- How many take part in games only?
- Show the above information in a Venn diagram.
Type: Long Difficulty: Easy
Q8:
Out of 40 students, 14 are taking English composition and 29 are taking Science. If 5 student are in both classes, how many students are in neither classes? How many students are in neither classes? How many students are in either class? Represented the above information in a Venn diagram.
Type: Long Difficulty: Easy
<p>Let U be the universal set.</p>
<p>Let E and S denote the sets of students taking English and Science respectively.</p>
<p>Then, n(U)=40, n(E)=14, n(S)=29 and n(E∩S)=5</p>
<p>We have, n(E∪S)=n(E)+n(S)-n(E∩S)</p>
<p>=14+29-5</p>
<p>=43-5</p>
<p>=38</p>
<p>Hence, there are 38 students in at least one of the classes.</p>
<p>Also,n\(\overline{E∪S}\)) =n(U) –n(E∪S)</p>
<p>40-38=2</p>
<p>Hence, 2 students are taking neither classes.</p>
<p>Finally, we represented the above information in a Venn-diagram</p>
<figure class="inline-left" style="width: 300px;"><img src="/uploads/ex_3.png" alt="." width="257" height="226" />
<figcaption></figcaption>
</figure>
Q9:
If n(U) = 40, n(A) = 25, n(B) = 10 and n(A\(\cap\)B) = 5 find:
i. n(A\(\cup\)B)
ii. n(\(\overline{A}\))
iii. no(A)
iv. no(B)
Type: Short Difficulty: Easy
<p>n(U) = 40, n(A) = 25, n(B) = 10 and n(A∩B) = 5</p>
<p>n(A∪B) = n(A) + n(B) - n(A∩B)= 25 + 10 - 5 = 30</p>
<p>n(\(\overline{A}\)) = n(U) – n(A) = 40 - 25 = 15</p>
<p>n<sub>o</sub>(A) = n(A) - n(A∩B) = 25 - 5 = 20</p>
<p>n<sub>o</sub>(B) = n(B) - n(A∩B) = 10 - 5 = 5</p>
Q10:
Let U ={1,2,.....,8,9}, A={1,2}, B={1,2,3,4,5}. Verify the following:
\(\overline{A∪B}\) =\(\overline{A∩B}\)
\(\overline{A∩B}\) =\(\overline{A∪B}\)
Type: Long Difficulty: Easy
Q11:
There are 20 people in a room. Of these,15 are holding newspaper and 8 are wearing glasses.Everyone wears glasses or holds newspapers. How many people are wearing glasses and holding a newspaper?
Type: Long Difficulty: Easy
Q12:
In a class there are 30 students, 21 students like Maths,16 students like English, 6 students don't like like Maths or English.How many students like both Maths and English?
Type: Long Difficulty: Easy
Q13:
Determine whether the following sets is null set or not.
- X = {x: x2 = 9, 2x = 4}
- Z = {x: x + 8 = 8}
Type: Short Difficulty: Easy
Q14:
Let A = {x :3x = 6}. Does A = 2?
Type: Short Difficulty: Easy
<p>A = {x : 3x = 6} = {2}</p>
<p>A is the set which consists of the single element 2 i.e A = {2}. The number 2 belongs to A, it does not equal to A. There is a basic difference between an element p and the singleton set {p}.</p>
Q15:
In a Class, there are 8 students who play football and hockey, 7 students who don't play football or hockey and13 students play hockey, 19 students play football. How many students are there in class?
Type: Long Difficulty: Easy
Q16:
Let, U = { 1,2,3........9}, A={2,3,4,5} and B ={4,5,6,7}, Find AUB, A∩B, A-B, B-A,\(\overline{A}\) and \(\overline{B}\).
Type: Long Difficulty: Easy
Q17:
If P={factors of 12} and Q= {factors of 8} Find.
Type: Long Difficulty: Easy
Q18:
Given that A={0,1,2,3,4,5}, B={0,2,4,6,8} & C={0,3,6,9}.Show that
AU(BUC) = (AUB)UC
Type: Long Difficulty: Easy
Q19:
If A = {0, 1, 2, 3, 4, 5}, B = {0, 2, 4, 6, 8} and C= {0, 3, 6, 9}. Prove, AU(B∩C) = (AUB)∩(AUC).
Type: Long Difficulty: Easy
<p>L.H.S = AU(B∩C)</p>
<p>= {0,1,2,3,4,5} U [{0,2,4,6,8}∩ {0,3,6,9}]</p>
<p>= {0,1,2,3,4,5} U {0,6}</p>
<p>= {0,1,2,3,4,5,6}</p>
<p>R.H.S = (AUB) ∩ (AUC)</p>
<p>= [{0,1,2,3,4,5} U {0,2,4,6,8}] ∩ [{0,1,2,3,4,5} U {0,3,6,9}]</p>
<p>= {0,1,2,3,4,5,6,8} ∩ {0,1,2,3,4,5,6,9}</p>
<p>= {0,1,2,3,4,5,6}</p>
<p>∴ L.H.S =R.H.S Proved</p>
Q20:
If A = {a,b,c,d,e} and B= {c,d,e,f,g}. Find A - B.
Type: Short Difficulty: Easy
Q21:
From the given diagram, Show the relationship between A and B.
a) n(A)
b) n(B)
c) n(A∩B)
d) n(AUB)
e) n0(A)
f) n0(B)
g) n(\(\overline{A}\))
i) n(\(\overline{B}\))
Type: Short Difficulty: Easy
Q22:
If A = {2, 4, 6, 8, 10} and B = {4, 8, 10,12,14}. Find
(A-B) U (B-A).
Type: Short Difficulty: Easy
Q23:
If, U = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14}, A={0, 1, 2, 3, 4, 5}, B={4, 5, 6, 7, 8} and C={2, 3, 4, 8, 9}. Find
a) A∪B∪C
b) \(\overline{A∪B∪C}\)
Type: Short Difficulty: Easy
<p>Given information,</p>
<p>a) A∪B∪C = {0, 1, 2, 3, 4, 5} ∪ {4, 5, 6, 7, 8} ∪ {2, 3, 4, 8, 9}</p>
<p>= {0, 1, 2, 3, 4, 5, 6, 7, 8} ∪ {2, 3, 4, 8, 9}</p>
<p>= {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}</p>
<p>b) ( \(\overline {A∪B∪C}\)) = U - A∪B∪C</p>
<p>= {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14} - {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}</p>
<p>= {10, 11, 12, 13, 14}</p>
<p> </p>
Q24: if n(a)=75%, n(B) = 80%,n(A intersectoin B) = 350 and n(complement of A U B)=15%, find n(U).
Type: Short
Difficulty: Easy
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Wind
Our earth is surrounded by an atmosphere. If the air in the atmosphere moves, then it is called wind. If air blows fast, then it is called storm. To have equal pressure in all areas is the nature of air. But, air cannot maintain equal pressure in all areas due to the change in temperature. As the sun warms the Earth's surface, the atmosphere warms too. Some parts of the earth receive direct rays from the sun whole year and are always warm. Other places receive indirect rays, so the climate is colder. Warm air weighing less than cold air rises. Then cool air moves in and replaces the rising warm air. This movement of air is what makes the wind blow.
Wind is the moving air and is caused by differences in air pressure within our atmosphere. Wind is able to lift roofs off buildings, blow down power lines and trees, and cause highway accidents as gusts push down cars and trucks. The two factors that are necessary to specify wind are speed and direction. The direction of the wind is expressed as the direction from which the wind is blowing. Winds have different levels of speed, such as 'breeze' and 'gale', depending on how fast they blow. The speeds of wind are based on the descriptions of winds on a scale called the Beaufort scale, which divides wind speeds into 12 different categories, from less than 1 mph to more than 73 mph.
If the air pressure of any place decreases due to a gradual increase in temperature, then the air blows from all the sides in that area which increases the amount of air increases in the area. Then air moves upward in spiral motion which is called a hurricane. It is called hurricane or tornado in America whereas it is called Typhoon in Japan. The hurricane occurring near the coastal areas is very powerful. It is also called a tsunami. There is high rainfall and storm while tsunami occurs. People living in coastal areas should always carry a radio with them so that they can get the forecast of a tsunami occurring there. By doing this, lives of people along with their property can be saved. During and after the hurricane, nobody should walk out from their homes. During storm or hurricane, we should not stay near the electric poles, electric wires, trees etc. We should not go to the areas where the hurricane is occurring. We must stay far from it.
Lesson
Our Earth
Subject
Social Studies and Population Education
Grade
Grade 8
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