Prep for Final PHYSICS Page 5 of 7 6 5 pointssercp10 6p023nv

Prep for Final PHYSICS Page 5 of 7 6. -/5 pointssercp10 6.p.023.nva A 45.0-kg girl is standing on a 158-kg plank. The plank, originally at rest, is free to slide on a frozen lake, which is a flat, frictionless surface. The girl begins to walk along the plank at a constant velocity of 1.36 m/s to the right relative to the plank. (Let the direction the girl is moving in be positive. Indicate the direction with the sign of your answer.) (a) What is her velocity relative to the surface of ice? (No Response) m/s (b) What is the velocity of the plank relative to the surface of ice? (No Response) m/s

Solution

(a) The velocity of the girl relative to the surface of ice is +1.36 m/s

(b) Using law of conservation of momentum, the velocity of the plank is 45X1.36 /158 =0.3873 m/s

Hence the velocity of the plank with respect to the surface of ice is - 0.38 m/s