Question

A cylinder of circumference 8 cm and length 21 cm rolls without sliding for `4 1/2` seconds at the rate of 9 complete rounds per second. Find the distance travelled by the cylinder in `4 1/2` seconds.

Answer 1

Circumference of cylinder = 8 cm 

Therefore, radius = `c/(2pi) = (8 xx 7)/(2 xx 22) = 14/11 cm`

Length of the cylinder (h) = 21 cm

If distance covered in one revolution is 8 cm, then distance covered in 9 revolution = 9 × 8 = 72

Therefore, distance covered in `4 1/2` seconds

= `72 xx 9/2 cm`

= 324 cm