A 45.0 kg girl is standing on a 169 kgplank. The plank, originally at rest, is f

Question

A 45.0 kg girl is standing on a 169 kgplank. The plank, originally at rest, is free to slide on a frozenlake, which is a flat, frictionless surface. The girl begins towalk along the plank at a constant velocity of 1.47 m/s relative to the plank. (a) What is her velocity relative to thesurface of ice?
1 m/s

(b) What is the velocity of the plank relative to the surface ofice?
2 m/s (a) What is her velocity relative to thesurface of ice?
1 m/s

(b) What is the velocity of the plank relative to the surface ofice?
2 m/s

Explanation / Answer

   let us take that
   vgi = velocity of the girl relative to theice
   vpi= velocity of the planck relative to theice
   vgp = 1.47 m / s
   from the given problem we can write
   vgi = vgp + vpi
   vgi = 1.47 m / s + vpi.......... (1)
(a)
   according to the law of conservation of momentum weget
   mg vgi + mpvpi = 0
   vpi = - (mg / mp)vgi........(2)
   from (1) we get
   [1 + (mg / mp) vgi] =1.47 m / s
   vgi = ....... m / s
(b)
   using the equation (2) we get
   vpi = - (mg / mp)vgi
        = ....... m / s(directed opposite to the motion of the girl)

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

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