What is the rotation angular velocity of the stopwatch? If the length of the second hand is 1cm, what is the centripetal acceleration of the end of the second hand

What is the rotation angular velocity of the stopwatch? If the length of the second hand is 1cm, what is the centripetal acceleration of the end of the second hand

The angular velocity of the second hand w = 60s / 2 π = 30 / π rad / S
∴a=rw²=9/（π²） m/s²

The second hand of a watch is 1.3cm long and the minute hand is only 1.2cm long. What is the linear velocity of the movement of the second hand and the minute hand tip? What is the angular velocity of the rotation of the second hand and the minute hand?

Angular velocity: all are "Pi of 30" (radians per second), where "Pi" is 3.14159
Linear speed: the linear speed at the end of the hand can be obtained by multiplying the length of the hand by the angular speed, so the second hand is about 0.136 cm / s and the minute hand is about 0.126 cm / s
That's all.

Angular velocity of minute hand and second hand of mechanical watch: ω min = 2 π / 3600rad / s, ω s = 2 π / 60rad / S
The time interval from the first coincidence of minute hand and second hand to the second coincidence is △ t
φ minutes = ω minutes △ t φ seconds = ω seconds △ t
φ s - φ min = 2 π
How can I get the last step 2 π, and what time does △ t mean?

Delta T can calculate the number of times that the second hand and the minute hand overlap in 60 minutes is 59, so their interval time is 60 / 56 min. (many people think that the number of times that the minute hand and the second hand overlap in an hour is 60 because they count in the two times that the first time and the last time overlap in 12 minutes, For example, if it overlaps once in 0 minutes and 0 seconds, it will not reach the first overlap in 1 minutes and 0 seconds, but the time has passed 60 seconds, and it will be overlapped a little bit in 1 minutes and 01 seconds, then it will be more than 60 seconds, so if it overlaps 60 times, then the interval is 1 minute, which is obviously wrong, The unit is rad. In fact, it's not necessary to calculate. 2 π is right, because 2 π is 360 degrees. Just think about it in your mind or draw a picture on the paper. Subtracting the overlapping position of the clock and the passing angle of the minute hand and the second hand is a circular angle