Question

A table clock has its minute hand 9 cm long. What is the average velocity of the tip of the minute hand (a) between 3 am to 3:30 am and (b) between 3 am to 3 pm?

Answer 1

a) `0.01 "cm"/"s"`
b) `0 "m"/"s"`

Explanation:

This is an edit to my previous wrong answer. Apologies for any inconveniences.

`"Velocity"="Displacement"/"time"`

`9cm = 0.09m`

a) From 3am to 3:30 am, it makes `1/2` revolution in `30 "min" =30*60 "s"`

But, the displacement of the tip is just 2 × length of the minute hand.

So, `v=(2*0.09)/(30*60)`

`=>v=0.0001"m"/"s" " OR " 0.01 "cm"/"s"` to 5 s.f

b) From 3am to 3 pm, it completes 12 revolutions.
But the displacement is 0 (it's returns to the same point at the label 12).
So, `v=0/12*60*60 = 0"m"/"s"`