Question

A pencil is tied to one end of a string of length 5 cm and the other is fixed to a nail. If the time taken to draw a half circle and a full circle, with the pencil is 2 and 4 4 seconds, respectively, find the speed and velocity pecil
(a) to draw half circle is drawn.
(b) when full circle is drawn

Answer 1

(a) Distance covered to draw half circle, `s=pir`
`=(22)/(7)xx5cm`
Dispplacment `=2r=2xx5=10cm`
Time taken =2s
`:. "Speed"=("Distance")/("Time")=(5pi)/(2) cm s^(-1)`
`"Velocity"=("Displacement")/("Time")=(10)/(2)=5 cm s^(-1)`
(b) Distance covred to draw full circle `=2pixx5=10picm s^(-1)`
Displcement =0
Time taken =4 s
`"Speed"=("Distance")/("Time")=(10pi)/(4)=(5pi)/(2) cm s^(-1)`
Velocity =0