Question

The length of the second hand of a clock is $4cm$ the speed of the tip of the second hand is:

• A. $0.24cm/s$
• B. $0.32cm/s$
• C. $0.42cm/s$
• D. $0.50cm/s$

Answer 1

The correct option is C $0.42cm/s$

$0.42cm/s$

circumference $=2\pi r$

$=2\times \frac{22}{7}\times 4$

$=25.1cm$

time taken to complete one round $=60s$

distance = speed×time

$s=\frac{25.1}{60}=0.419\approx 0.42cm/s$