Kan någon förklara hur man kommer till rätta svaret? Föstår inte riktigt frågan
A cord is wrapped onto a cylindrical reel mounted on a fixed, frictionless, horizontal axle. When does the reel have a greater magnitude of angular acceleration?
http://i68.tinypic.com/10zd0gn.gif
(a) When the cord is pulled down with a constant force of 50 N.
(b) When an object of weight 50 N is hung from the cord and released.
(c) The angular accelerations in parts (a) and (b) are equal.
(d) It is impossible to determine.
Tacksam på förhand!