- #1
teresalin2004
- 2
- 0
Homework Statement
At a playground you let your kid sister (30 kg) kneel on the surface (near the edge) of a 2.1 meter diameter merry-go-round. You push the merry-go-round so that it constantly accelerates from rest to a final speed of 1.7 rotations per second at the end of a 25 second interval. (please complete all questions using radians)
After it comes up to speed, you stop pushing and the merry-go-round continues to run at a constant rate of 1.7 rotations per second. What is the magnitude of your sister's acceleration, if any?
Homework Equations
V is the tangental velocity in m/s
r is radius of circle in meters
ω is angular velocity in radians/sec
a is in m/s²
[/B]
1.7 rotations per second x 2π rad/rev = 10.68 rad/s
ang. acc. = Δω/Δt = 10.68/25 = 0.427 rad/s²
134 rad x 1 rev/2πrad = 21.25 rev
The Attempt at a Solution
I got the first part of the question right, but I have no idea what I am doing wrong for the last part shown above. This is what I did:
a = rω² = (2.1)(10.68)² = 240 m/s²
[/B]