Question

In a regular cone, the angle between base and slanting surface is 45 degrees and the base diameter is 100 mm. If a helix is to be built on such a cone with a pitch of 5. How many revolutions do the helix made in this cone?

(a) 14.1

(b) 18

(c) 10

(d) 20

The question was posed to me in unit test.

My question is from Helix upon a Cone topic in portion Curves used in Engineering Practice of Engineering Drawing

Answer 1

Right option is (c) 10

Easy explanation: Given angle between the base and slanting surface is 45 and the diameter of the base is 100 mm height of a cone is 100/2 x tan (45) =50. Pitch of helix is 5. Number of revolutions = total length of helix/ pitch of helix = 50/5 = 10.