Understanding of rotational motion

AI Thread Summary
Understanding rotational motion involves concepts like tangential speed, angular momentum, and centripetal force. When considering an automobile speedometer calibrated to measure the tangential speed of its wheels, increasing the wheel size results in a higher tangential speed due to the larger radius. The equation v = rω illustrates that as the radius (r) increases, the tangential speed (v) also increases, leading to a higher speedometer reading. Therefore, larger wheels will cause the speedometer to display a higher speed. This relationship highlights the importance of wheel size in determining speedometer accuracy.
acoult
Messages
4
Reaction score
0
Hello anyone that can help. I am trying to gain an understanding of rotational motion, including (tangential speed, angular momentum, centripetal force and so on). The first question I was hoping that someone could help me is:

An automobile speedometer is configured yo read speed proportional to the rotational speed of its wheels. If larger wheels are used, will the speedometer reading be higher, lower or the same.



I understand the question but I was hoping someone could help explain this to me in a mathamatical equation.


Thank you for your help. I promise not to bug you guys to much!
 
Physics news on Phys.org



Hello there,

To answer your question, let's first define the terms involved in rotational motion.

- Tangential speed refers to the speed of an object moving along a circular path. It is measured in units of distance per time (such as meters per second or kilometers per hour).
- Angular momentum is a measure of an object's rotational motion, and it is calculated by multiplying the object's moment of inertia (a measure of its resistance to rotational motion) by its angular velocity (how fast it is rotating). It is measured in units of mass times distance squared per time (such as kg*m^2/s).
- Centripetal force is the force that keeps an object moving along a circular path. It is always directed towards the center of the circle and is equal to the product of the object's mass, tangential speed squared, and the radius of the circle. It is measured in units of force (such as Newtons).

Now, let's apply these concepts to your question about the automobile speedometer.

Assuming that the speedometer is calibrated to measure the tangential speed of the wheels, we can use the equation for tangential speed (v = rω) to understand the relationship between wheel size and speedometer reading.

In this equation, v represents the tangential speed, r represents the radius of the wheel, and ω represents the angular velocity (how fast the wheel is rotating).

If we increase the size of the wheels (meaning the radius, r, becomes larger), the tangential speed (v) will also increase. This is because the larger wheel will have a greater distance to travel in one rotation, resulting in a higher tangential speed.

Now, let's look at the speedometer reading. As we mentioned, the speedometer is calibrated to measure tangential speed. So, if the tangential speed increases, the speedometer reading will also increase. This means that the speedometer reading will be higher when larger wheels are used.

To summarize, the equation for tangential speed (v = rω) can help us understand the relationship between wheel size and speedometer reading. Increasing the wheel size (r) will result in a higher tangential speed (v) and therefore a higher speedometer reading.

I hope this helps to clarify your understanding of rotational motion and the relationship between wheel size and speedometer reading. Feel free to ask any further questions you may have. Good luck with your studies
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...

Similar threads

Back
Top