Very Simple Angular Physics Problem

In summary, the conversation is about a person who is struggling with a rotational problem involving tangential velocity on a clock. They incorrectly use the formula v= w(angular velocity)r and get a value of 155.3µm/s. They then realize their mistake and correctly calculate the tangential speed as 2pi*r/ (3600)(24) = 155.3µm/s. They also discuss the time it takes for the hour hand to make one complete revolution, which is 12 hours, not 24 hours as there are 24 hours in a day.
  • #1
chrispsu
23
0
Hi there, brand new to the site. Came across it when googling for help on tangential velocity in a rotational problem.
Anyhow I have an online homework due at midnight and would love to have any help possible with this question before then.

Heres the problem...
The hour hand on a certain clock is 8.9 cm long. Find the tangential speed of the tip of this hand in µm/s.

I tried v= w(angular velocity)r
so v= 2pi*r/ (60)(60) and got 155.3µm/s

This however is incorrect and any help to lead me the right way is greatly appreciated :D

Im an A student in Physics but just don't grasp rotation as well as the other topics.
This question is probably very simple but it is just not clicking for me, maybe I am missing the correct formula to use?
 
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  • #2
How long does it take the hour hand of a clock to make one complete revolution?
 
  • #3
Noein said:
How long does it take the hour hand of a clock to make one complete revolution?

3600 sec which is why i divided by that...is that not correct?:confused:
 
  • #4
One hour is equal to 3600 s. This is not the total time it takes the hour hand to make one complete revolution, however.
 
  • #5
Noein said:
One hour is equal to 3600 s. This is not the total time it takes the hour hand to make one complete revolution, however.

oh damn so i should multiplying 3600 * 24 then too!

see i knew i was making a dumb mistake, thanks alot! :D
 
  • #6
There are 24 hours in a day. But, when the hour hand of a clock goes around once, how many hours has it gone through?
 
  • #7
Noein said:
There are 24 hours in a day. But, when the hour hand of a clock goes around once, how many hours has it gone through?

ahhh 12, tricky, tricky
 

Related to Very Simple Angular Physics Problem

1. What is the definition of angular physics?

Angular physics is a branch of physics that deals with the motion of objects in a circular or rotational motion. It involves the study of forces, torque, and energy in relation to angular motion.

2. What is the difference between linear and angular physics?

Linear physics deals with the motion of objects in a straight line, while angular physics deals with the motion of objects in a circular or rotational motion. The fundamental principles of forces and energy are the same in both branches, but their application and calculations differ.

3. What is the formula for calculating angular velocity?

The formula for calculating angular velocity is angular displacement divided by time. It is represented as ω = θ/t, where ω is the angular velocity in radians per second, θ is the angular displacement in radians, and t is the time in seconds.

4. How do you calculate angular acceleration?

Angular acceleration is calculated by dividing the change in angular velocity by the change in time. It is represented as α = (ω2 - ω1) / (t2 - t1), where α is the angular acceleration in radians per second squared, ω2 and ω1 are the final and initial angular velocities, and t2 and t1 are the final and initial times.

5. What is the relationship between angular and linear velocity?

Angular and linear velocity are related by the radius of the circular motion. The linear velocity of an object in circular motion is equal to the angular velocity multiplied by the radius. It can be represented as v = ωr, where v is the linear velocity, ω is the angular velocity, and r is the radius of the circular motion.

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