Why Use Angular Acceleration Instead of Radial?

AI Thread Summary
The discussion centers on calculating the apparent weight of a passenger on the cosmoclock 21 Ferris Wheel, focusing on the confusion between using radial and angular acceleration. The passenger's speed is correctly calculated at 5.235 m/s, but the apparent weight calculation initially used radial acceleration, leading to an incorrect result. The correct approach involves using angular acceleration, which aligns with the physics principles for circular motion. The participant acknowledges a mistake in using diameter instead of radius in their calculations. The conversation emphasizes the importance of understanding the distinction between radial and angular acceleration in such problems.
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Homework Statement


The cosmoclock 21 Ferris Wheel in Yokohama City, Japan, has a diameter of 100m. Its name comes from its 60 arms, each of which can function as a second hand (so it makes one revolution every 60.0s).

a) Find the speed of the passengers when the Ferris wheel is rotating at this rate [No problem]
b) A passenger weighs 882N at the weight-guessing booth on the ground. What is his apparent weight at the lowest point of the ferris wheel?

Homework Equations


d = vt
arad = v^2.r
w = mg

The Attempt at a Solution


I have no problem with part a.

distance = 2pi r = 314.1m
velocity = 314.1/60 = 5.235m/s

It is part b where I get confused. I get it right till the step to use acceleration. I use radial acceleration and get it wrong, googled the question and someone used angular acceleration. I used his angular acceleration value and my answer was correct. But I am wondering why use angular acceleration instead of radial?

Weight on ground = 882N
Mass = 89.9 kg

F = ma
Nb - mg = ma
Nb = m (a +g)

*This is the part where I use radial acceleration
a = v2/r
a = 0.1745m/s2

Nb = 89.9 (0.1745+9.81)
Nb = 897.6N
 
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Hi, welcome to physicsforums :)
the equation you are using a=v2/r is the correct one. And your value for the velocity is good. I think you made a mistake in doing the calculation v2/r. what values did you use? Remember you should be using radius, not diameter.
 
Hey Bruce! Haha you are right! Opps! Thank you!
 
no worries! glad to help :) Your method was good.
 
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