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ML Aggarwal Solutions Class 9 Mathematics Solutions for Mensuration Exercise 16.3 in Chapter 16 - Mensuration

Question 5 Mensuration Exercise 16.3

A bucket is raised from a well by means of a rope that is wound around a wheel of diameter 77 cm.

Given that the bucket ascends in 1 minute 28 seconds with a uniform speed of 1.1 m/sec, calculate the

number of complete revolutions the wheel makes in raising the bucket.

Answer:

It is given that

Diameter of wheel = 77 cm

So the radius of the wheel = 77/2 cm

We know that

Circumference of wheel = 2πr

Substituting the values

= 2 × 22/7 × 77/2

= 242 cm

Video transcript
"hello and welcome my dear students i am rishikurana the match with leader and i'm here the new question it is a bucket is raised from a well by means of a rope that is that is around a wheel of diameter 77 centimeter given that the bucket ascends in one minute 28 seconds with a uniform speed of 1.1 meter per second calculate the number of complete revolutions the wheel makes in the raising the bucket before actually getting into the question let's look at the few important points of the question so in this question we have been given that the wheel has a diameter of 77 centimeter whereas the bucket ascends in one minute 28 seconds with a uniform speed of 1.1 meter per second and we are supposed to calculate the number of revolutions so let's look at the solution so we have been given the diameter i am writing d for diameter so diameter field is nothing but 77 centimeter which means at the radius r is nothing but 77 by 2 centimeter if we convert into meters we get 77 by 200 meters also we know that the circumference circumference of circle is equals to 2 pi r now substituting the values we get 2 into 22 by 7 into r which is 77 by 200 solving which we get the answer as 2.4 to meters now also in the question we have been given the speed and the time so i'm writing s for the speed so s that is speed is given as 1.1 meter per second whereas the time is given as writing t for time is given as one minute 28 seconds which is nothing but equals to 88 seconds now if we calculate the total distance that is covered so we all know that distance is equal to speed into time which is nothing but 1.1 into 88 following which we get 96.8 meter as the total distance now to get the total number of revolutions i'm adding rev for the revolutions that is equal to distance upon circumference solving which we get we'll first substitute the value so 96.8 divided by 2.42 we get 40 revolutions as the answer that means the total number of revolutions is equals to 40 so i hope my students got this question well do not forget to hit the subscribe button you can also share your doubts in the comment section see you next time bye bye"
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