Question

State true or false:

A cylinder of circumference $8$ cm and length $21$cm rolls without sliding for $4\frac{1}{2}$ seconds at the rate of $9$ complete rounds per second. Find the distance travelled by the cylinder in $4\frac{1}{2}$ seconds, and
Answer: 324 cm

Distance travelled by the cylinder in 1 round $=$ its circumference

• A. True
• B. False

Answer 1

The correct option is A True

Given , A cylinder with circumference 8 cm and length 21 cm.
Number of round per second$=$ 9
Number of round in $4\frac{1}{2}$ seconds $=4\frac{1}{2}\times 9$
$=\frac{81}{2}$
Distance traveled by cylinder in 1 round$=$ circumference of cylinder
Distance traveled by cylinder in $\frac{81}{2}$ rounds =$\frac{81}{2}\times$ circumference
$=\frac{81}{2}\times 8=324$ cm