An ice skater can spin much faster by pulling in her arms. This is an illustrati

Question

An ice skater can spin much faster by pulling in her arms. This is an illustration of which fundamental principle in physics? a. conservation of angular momentum b. conservation of linear momentum c. conservation of kinetic energy d. conservation of mechanical energy A puck attached to a string moves in a circular path on a frictionless surface as shown. Initially, the speed of the puck is v and the radius of the circle is r. If the string passes through a hole in the surface, and is pulled downward until the radius of the circular path is 0.4 r, what is the final speed of the puck? a. 3.0 v b. 5.0 v c. 2.5 v d. 1.5 v

Explanation / Answer

19.

(a) conservation of angular momentum.

20.

Let, final speed of puck = v'

From conservation of Angular momentum,

Linitial = Lfinal

mvr = mv'(0.4r)

v' = 2.5v

Final speed of puck v' = 2.5v (option c).

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.