Question

Wilhelmina is an avid ice skater who is also taking physics with her friend Darcy. Wilhelmina is having a discussion with Darcy and is trying to relate her skating experience to the discussions in class about rotational kinetic energy and angular momentum.
Darcy reminds Wilhelmina that the instantaneous angular momentum, , of a particle relative to an axis through an origin O is defined by the cross product of the particle's instantaneous position vector relative to O, , and its instantaneous linear momentum, .
The friends use the simulation, which depicts a top view of an ice skater, to explore angular momentum. As the skater passes a pole (represented by the dark circle), she grabs hold, causing her body to swing around rapidly in a circular path. The friends can use the sliders to vary the speed and arm extension for the skater, and they can click" start" to begin the animation. They assume that the ice is frictionless, and that air resistance makes a negligible contribution to the motion.

Darcy and Wilhelmina now tackle a homework problem.

An ice skater of mass m = 60 kg coasts at a speed of v = 1.87 m/s past a pole. At the distance of closest approach, her center of mass is r₁ = 0.44 m from the pole. At that point she grabs hold of the pole.

(A) What is the skater's angular speed when she first grabs the pole?
______ rad/s

(B) What is the skater's angular speed after she now pulls her center of mass to a distance of r₂ = 0.3 m from the pole?
_________ rad/s

Answer 1

tomor= 60x1.8770.46 49.368 kynys I= mr2 = 60x10.44) 11.616 kg me 49. 368 → 4-25 rad ^) W- _ : 49.368 >> 4-25 rools 11.616 B 1. Jiw,-1,W2 Iz » mr. ² = 60 x0.3)*) 5-4 kam? W, * } = 434 79.142 rolls Scanned with CamScanner