Rotational kinematics of analog clock

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SUMMARY

At 10:00, the hour hand of an analog clock is positioned 300 degrees ahead of the minute hand. To determine when the minute hand next aligns with the hour hand, one must apply rotational kinematics principles. The speeds of the hour and minute hands are critical: the hour hand moves at 0.5 degrees per minute, while the minute hand moves at 6 degrees per minute. The next alignment occurs when the minute hand catches up to the hour hand, which can be calculated by setting up an equation based on their relative speeds.

PREREQUISITES
  • Understanding of rotational kinematics
  • Knowledge of angular velocity (degrees per minute)
  • Ability to set up and solve equations
  • Familiarity with the mechanics of analog clocks
NEXT STEPS
  • Calculate the angular velocities of clock hands in detail
  • Learn to derive equations for relative motion in rotational systems
  • Explore the concept of angular displacement in practical scenarios
  • Investigate other rotational motion problems involving gears and wheels
USEFUL FOR

Students studying physics, educators teaching rotational motion, and anyone interested in solving mechanical problems involving analog clocks.

Chrisleo13
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When it is 10:00, the hour hand on an analog clock is 300 ahead of the minute hand. How many minutes elapse (to three significant digits) before the minute hand next points in the same direction as the hour hand?


I seems really easy, but for some reason I am not getting the right answer.

Can I use rotational kinematics?
 
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Chrisleo13 said:
When it is 10:00, the hour hand on an analog clock is 300 ahead of the minute hand. How many minutes elapse (to three significant digits) before the minute hand next points in the same direction as the hour hand?I seems really easy, but for some reason I am not getting the right answer.

Can I use rotational kinematics?

Looks like a logic problem.

Write an equation for the motion of the hands of a clock. What is the speed of the hour hand? What is the speed of the minute hand.

Then figure the next time the hands have the opportunity to be 300 degrees apart again and create an equation that takes into account the effect of both the hand in getting to be exactly 300 degrees apart.
 


First of all, think what is the next time after 10.00 where the two hands of a clock are on top of each other? That's essentially your answer - the only time the hands of a clock are pointing in the same direction is when they're on top of one another.
 

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