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Unformatted text preview: bro 1’ UTl 0 MS  Total grade: PH 1110 Summary Homework 3, C Term 2008 Name . Section Number This assignment is worth 2.5% of your ﬁnal grade and is our recommended means for you to assess
your readiness for Exam 3. It is due in conference on Tuesday, February 12 and will be available for you on Thursday, February 14, the day before Exam 3. Pleasc Show your work and report your
1 anSWers to no more than three signiﬁcant ﬁgures. Place your answers in the boxes, where provided. la. [1 Opts] In Lab 5, the masses and hanger are connected to the cart by a string, just as in the picture in
the overview of the lab instructions, or as in the sketch on the left below. Please draw vectors E representing the forces acting on the masses and hanger (up), as well as the cart on the sloped track (ma), making sure to label the forces clearly. Draw vectors consistent with velocity down the slope and acceleration up the slope. Friction acts with a friction coefﬁcient of u.  T
i d "N05 Ma‘s
Experimental set—up Masses and hanger Cart
a. 1b. [10 pts] Then based on the forces shown in these freebody diagrams, write out terms representing the
(3; work done on the bodies asutjhe cart ﬁrst moves down, then up, the slope a distance 8 (round—trip ' , : ._. ‘ S =—" O
d1stance 28) W mhs W‘k c3 5 + Wing
. I WT ; TAM“ Sq “' Twp 5 ._..—— Cari“ \NN =0 (e :90”) lo. [10 pts] Use theabove equations to ﬁnd the total work done on the system of cart plus hanger. N — #2115 ﬁznwznmcgcooe TOTAL "
Wm: S _1 d. [10 pts] If the system started from a speed vi, predict its speed, vf, alter the round trip.
 1 .L P
_Wrcrmt ‘ z®ﬁ+mg Us “’ 2(MNWQ Va .7 ‘JMMCSCG'DQS '1 W: [Vlmh wow 4W5)” ' ‘ ' mama "I ~3Mmcj 00065 (a ‘ thhYﬂc I 1 ' _ Points earned on thispage: l:l Summary Homework 3, continued. Name Section Number 2a. [5 pts] Reminiscent of Lab 6, in which you dropped a sandbag onto a force plate, a ball of putty, mass
mp, is thrown at a wall such that just before impact, the ball has velocity v = vx i — v3, j. The putty sticks to the wall. The wall does not measurably move and is not damaged. What is the impulse that
the ball received from the wall to make it stop? Pd “Nev ‘MPVK L "erJ
.2. Ps2“?
1;: A '2’ m \r f M «7 A
. 2 " a = n X + P , A
3 P P J1 J Jwallon bail = "Mp 2b. [5 pts] And what is the impulse that the wall received from the ball?
9;: “‘2’ ‘Tsatt #11 Wadi : F “eureka” . 4’1  A
Jballon wait = C p— J 2c. [5 pts] What is the work done on the ball by the wall? _
Wﬁmu .. Lia/Irv; _— lmyc. 0 . amp (’4'; "HA, ‘1 Va :2 Vx + Y7 \u M”; V? ’1: O Wwallonball= 2d. [5 pts] And What is the work done on the wall by the ball? _W‘¢°T&L ﬂ K". —{<5 :0 (waif 4,060 lem) 26. [10 pts] Is any meehanical energy lost during the collision? If so, where did it go? _  ' ' _
I  z . \ 1') K . 37L
imp (cg, «Hg/,7 :5 {a I 5;; _ 2m elsew Summary Homework 3, continued. Name Section Number 3a. [10 pts] Two skiers collide on a ﬂat icy patch of snow. Skier A, of mass m». = 50.0 kg, has initial
velocity v = (3.00 i  4.00 j) m/s. Skier B, of mass mg = 100 kg, has initial velocity v = (2.00 i +
100j ) m/s. They collide, their skis become entangled, and they slide (no friction) together. What is
their momentum (a vector) after the collision? Iii(vii W‘s ‘ «A W I A A
Pa; ' WIMCVA ~ ~[5oc ——ZooJ NS’
"e"; : MR7 : Zoo”? +1003 Ms . B A
M eD 4 A
has " “135* 5’2, pA+B= got 4005 Ns :: 504 1003 NS 3b. [10 pts] Sketch the momentum vectors on the graph, labeling them, and making sure to label and scale
the axes. There will be three vectors: one each for the skiers before the collision, pA and p3, and one
for both skiers, pA+B, after the collision. ‘ 3c. [10 pts]ghat is theimpulseg vector) of A on B? And B on A?
I ,e ‘ r fA+B 1" \ ~l00ﬂ]
M,‘ + M3 . 52) +10 0 J .5 a: A
ﬁlm: W"; “Wm J....=~tet,7z‘ wztéﬂj N.
(467“) —5‘0 ~39 n
.. .J  J =M’ A éé’A ﬂ
= mm? + 14.4.75 ms _ Juana :76 ti 70 N b
«=3: 4 I
EMS "’ ' ﬁrms 3 Points earned onthis page; :l l:
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This homework help was uploaded on 04/09/2008 for the course PH 1120 taught by Professor Keil during the Spring '08 term at WPI.
 Spring '08
 Keil

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