please try to answer I will mark you as brainlist
Answers
Answer:
Option (D): Distance covered in 100 revolution = 220 m
Step-by-step explanation:
I think you need to re do the entire chapter from basics because if this kind of questions you aint able to do, you will probably have difficulty later on. I'll try to explain you maybe you can apply this same logic to these kind of question and be able to solve and may not need to fear such questions ever again.
So,for this type of question you are supposed to be knowing formula of circumference of the circle and one more thing which I'll be discussing later.
Circumference of a circle :
- C = πd (in terms of diameter)
- C = 2πr (∵ d = 2r)
So both these formula you can use to find the circumference of the circle.
Now, circumference of the circle will be the distance covered by wheel in one revolution.
Imagine you are having a circle of radius 5 cm ( which means diameter = 10 cm). Now the circumference of the circle will be 2 × π × 5 which is 10π cm. So,if you stretch this circle into a straight line, you will find that the distance the line will spread to will be 10π cm. So, hence the circumference = distance covered in one revolution.
Now, using the above concept we can easily solve the given question.
Given :
- Diameter = 70 cm
- Number of revolution = 100
Circumference :
=> πd
=> 22/7 × 70
=> 22 × 10
=> 220 cm
Now,this is actually the distance covered in one revolution, meaning if you make this circle a straight line the distance to which it will spread will be 220 cm and we are given that wheel makes 100 revolutions,so we having such 100 lines each having length of 220 cm.
Mathematically :
Number of revolutions = Total Distance/ Distance covered in one revolution
We have been given that number of revolution is 100 and we calculated distance covered in one revolution which is 220 cm, substituting these values,
=> 100 = x/ 220
=> 100 × 220 = x
=> x = 22000 cm
Now, convert cm into m,to do so, divide by 100,
=> x = 22000/100
=> x = 220 m
∴ Distance covered by wheel in 100 revolution is 220m.
But if you don't want to remember all these hectic logic, what you can do is just calculate the circumference of the circle and multiply it by the number of revolutions given in the question, you will get the same answer. Let me show you.
We know that the circumference is 220 cm and the wheel makes 100 revolutions,so we will actually have 100 lines of 220 cm length each.
1 revolution → 220 cm
Multiply both side by 100 (because that's the number of revolution we need, you can multiply as per the number of revolution mentioned in the question),
=> 100 revolution = (220 × 100) cm
=> 100 revolution = 22000 cm
Now just convert cm → m and you get the same answer. It's really cake walk once you begin imagining circle as a straight line of infinite radius.
Answer:
(d) 220 m
Step-by-step explanation:
Distance covered in one revolution = πd
where d = diameter of wheel
→ Distance covered in one revolution = 22/7 × 70
→ Distance = 220 cm
Distance covered in 100 such revolutions = 220×100 (cm)
→ Distance = 22000 (cm)
In meters:
Distance = 22000/100 = 220 m