Yvette asked in Math

A rope which is wound round a drum of diameter 21cm is attached to a bucket that is resting at the bottom of a well of depth 9.89m.Find the number of complete turns of the handle required to bring up the bucket such that the bottom of the bucket is suspended just above the mouth of the well.

Thank You

Ankita Agarwal answered this

Dear Student, 

Depth of well = No. of turns × length of one turnGiven:   Depth of well = 9.89m = 989cm          [1m = 100cm] Let number of turns be x   Length of one turn = 2πr or π×diameter Now , 989=x×π×21989=x×227×21x=989×722×21x=14.98 15 turns     Number of turn never be in decimals Hence number of  15 complete turns of the handle required to bring up the bucket