Register to reply

Rotational Kinetic Energy

by rugbygirl
Tags: energy, kinetic, rotational
Share this thread:
rugbygirl
#1
Mar6-08, 11:56 PM
P: 5
A bicycle has wheels of radius 0.33 m. Each wheel has a rotational inertia of 0.082 kg* m2 about its axle. The total mass of the bicycle including the wheels and the rider is 74 kg. When coasting at constant speed, what fraction of the total kinetic energy of the bicycle (including rider) is the rotational kinetic energy of the wheels?

I thought this: Rotational KE = (1/2)Iw^2
=(1/2)(second bold number)w^2

Linear KE= (1/2)mv^2
= (1/2)(third bold number)(radius*w)^2 (i.e. plug in r*w for v)
Total KE is equal to Rotational KE + Linear KE
add the two eqns
(1/2)Iw^2/ (some # * w^2)
Phys.Org News Partner Science news on Phys.org
Suddenly, the sun is eerily quiet: Where did the sunspots go?
'Moral victories' might spare you from losing again
Mammoth and mastodon behavior was less roam, more stay at home
luben
#2
Mar7-08, 12:06 AM
P: 68
i think you are correct
eventually one takes away the w^2 in both numerator and denominator, then gets a result independent of w
rugbygirl
#3
Mar7-08, 12:16 AM
P: 5
i keep getting .041/4.07 and that is not right

Cyrus
#4
Mar7-08, 12:17 AM
Cyrus's Avatar
P: 4,780
Rotational Kinetic Energy

How many wheels does a bicycle have?

Please post in the HW forums.


Register to reply

Related Discussions
Rotational Kinetic Energy Introductory Physics Homework 2
Rotational Kinetic Energy Introductory Physics Homework 2
Rotational kinetic energy Introductory Physics Homework 1
PLEASE HELP - Rotational Kinetic Energy Introductory Physics Homework 6
Rotational Kinetic Energy Introductory Physics Homework 0