Please show: 1. “free body diagram” 2. “+ and - direction on the coordinated sys
ID: 306196 • Letter: P
Question
Please show: 1. “free body diagram” 2. “+ and - direction on the coordinated system”Thank you Et Starting from rest, two skaters push off against each other on ice where friction is negligible. One is a 54-kg woman and one is a 88-kg man. The woman moves away with a speed of +2.5 m/s. a) Explain why Linear Momentum is conserved. b) Find the recoil velocity of the man. c) If they were in contact for 0.5 seconds while irt pushing away from each other, find the average pushing force (magnitude and direction) acting on each of them. (a) Before u12 Uf1 (b) After
Explanation / Answer
a] In coordinate system, take rightward as +x axis (horizontal), and upward as +y axis.
On whole man-woman system, there is no external horizontal force, so momentum is conserved in x direction.
In y direction also forces are balanced as both normal and weight cancel out, so momentum is conserved in y direction also.
b] Final momentum = initial momentum = 0
54*2.5 + 88v = 0
v = -54*2.5/88
= -1.534 m/s answer
c] Average force on each = change in momentum of each/time
= 54*2.5/0.5 = 270 N
Force on woman = 270 N in + x direction
Force on man = 270 N in -x direction