find the ans to the question no. 2
Answers
2. The diameter of the wheel of a bullock cart is 0.56 m. Find the number of rotations the wheel makes to cover a distance of 2.2 km.
Answer:
Number of rotations = 1250
Step-by-step explanation:
Let's understand the question first. Here, we are provided with the diameter of a bullock cart i.e. 0.56 m. We need to find out the number of rotations the wheel makes to cover a distance of 2.2 km.
First find out the distance travelled by the wheel in a rotation (using the formula circumference of the circle). Given, that the diameter of the wheel is 0.56 m and it's radius will be half of the diameter (radius = diameter/2 = 0.56/2 = 0.28 m).
Circumference of circle = 2πr
Here, r is radius having value 0.28 m and value of π is 22/7. Substitute the values,
= 2 × 22/7 × 0.28
= 44 × 0.04
= 1.76 m
OR
Circumference of circle = 2πr
= π(2r)
= πd (d = diameter)
Therefore, the distance covered by the wheel in a rotation is 1.76 m. Now, apply the unitary method (a unit from a given multiple). Let's take an example to understand unitary method.
{ Cost of 2 pens = Rs. 10
Cost of 1 pen = 10/2 = Rs. 5
Cost of 4 pens = 5*4 = Rs. 20 }
As per question, we need to find out the number of rotations the wheel makes to cover a distance of 2.2 km. Now, circumference is in metres (given) whereas number of rotations is in kilometres. So, simply convert km into m; to make the units same. To do so, multiply by 1000. So, 2.2 km = 2200 m.
Let's say that in "n" number of rotations the wheel covers a distance of 2.2 km or 2200 m.
Number of rotations × Distance covered in 1 m = Distance covered in 2200 m
→ n × 1.76 = 2200
→ n = 2200/1.76
→ n = 1250
Therefore, the number of rotations the wheel makes to cover a distance of 2.2 km or 2200 m is 1250.