This preview shows pages 1–3. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: Physics 105: Mechanics Fall 2009 Homework 4 Solutions 2.P.39 SYSTEM = two rocks SURROUNDING = nothing significant All the speeds are in the range where γ ≈ 1. Δ ~ p tot = ~ F ext net Δ t = 0 . Initial: ~ p 1 i = m 1 i ~v 1 i = (9kg) h 4100 , 2600 , 2800 i m / s = h 36900 , 23400 , 25200 i kgm / s ~ p 2 i = m 2 i ~v 1 i = (6kg) h 450 , 1800 , 3500 i m / s = h 2700 , 10800 , 21000 i kgm / s ~ p tot,i = ~ p 1 i + ~ p 2 i = h 34200 , 12600 , 46200 i kgm / s Final: ~ p 1 f = m 1 f ~v 1 f = (7kg) h 1300 , 200 , 1800 i m / s = h 9100 , 1400 , 12600 i kgm / s Total momentum of system is conserved: ~ p 1 f + ~ p 2 f = ~ p 1 i + ~ p 2 i ~ p 2 f = ~ p 1 i + ~ p 2 i ~ p 1 f = h 25100 , 14000 , 33600 i kgm / s ~v 2 f = ~ p 2 f /m 2 f = h 3137 , 1750 , 4200 i m / s 2.P.45 System = junk + satellite Surroundings = no signficant forces exerted by other objects Assume γ = 1. Let ~v 4 be the final velocity of the center of mass of the satellite. Initial momentum of system (just before collision): ~ p sys,i = m~v 2 + M~v 1 . xcomponent: p sys,i,x = m  ~v 2  + M  ~v 1  . ycomponent: p sys,i,y = 0 . Final momentum of system (just after collision): ~ p sys,f = m~v 3 + M~v 4 . xcomponent: p sys,f,x = m  ~v 3  cos θ + Mv 4 ,x . ycomponent: p sys,f,y = m  ~v 3  sin θ + Mv 4 ,y . Since there are no significant external forces acting on the system during the collision, ~ p sys,i = ~ p sys,f . Thus v 4 ,x = m  ~v 2  /M +  ~v 1  + m  ~v 3  cos θ/M. v 4 ,y = m  ~v 3  sin θ/M. 3.RQ.27 The magnitude of the gravitational due to the Earth on a mass m located a distance r from the center of the Earth (where r > R E ) is  ~ F g  = GM E m/r 2 . If the object is at the surface of the Earth, r = R...
View
Full
Document
This note was uploaded on 03/10/2010 for the course PHYS 41 taught by Professor Lou during the Fall '09 term at Georgetown KY.
 Fall '09
 Lou
 mechanics, Work

Click to edit the document details