- #1
dalitwil
- 23
- 0
I already posted this somewhere, but silly me, i can't find it.
Q: A disk of radius 2.40 cm and mass 1 kg is pulled by a string wrapped around its circumference with a constant force of 0.36 Newtons. What is the angular velocity of the disk to three decimal places after it has been turned through 0.85 of a revolution?
So I started by obtaining my degrees from the 0.85 revolutions (S=rθ). This equals 2.225 degrees.
Next I used ∆x=R∆θ
(2.40)*(2.225)
=5.340 radians
W=F∆x
(0.36)*(5.340)
=1.9224
Using conservation of work (W=∆K):
K=.5Iω^2 (where I of a disk=.5MR^2)
W=1.9924=.5(.5*1*2.4^2)ω^2
ω=1.15542
WRONG. I can't figure out where I am going wrong, please help!
Q: A disk of radius 2.40 cm and mass 1 kg is pulled by a string wrapped around its circumference with a constant force of 0.36 Newtons. What is the angular velocity of the disk to three decimal places after it has been turned through 0.85 of a revolution?
So I started by obtaining my degrees from the 0.85 revolutions (S=rθ). This equals 2.225 degrees.
Next I used ∆x=R∆θ
(2.40)*(2.225)
=5.340 radians
W=F∆x
(0.36)*(5.340)
=1.9224
Using conservation of work (W=∆K):
K=.5Iω^2 (where I of a disk=.5MR^2)
W=1.9924=.5(.5*1*2.4^2)ω^2
ω=1.15542
WRONG. I can't figure out where I am going wrong, please help!