Download 4 Solved Problems on Simple Harmonic Motion - Exam 2 | PHYS 1150 and more Exams Physics in PDF only on Docsity! GS
Exam 2 NAME: Fob dps
Physics I Honors,
PHYS 1150, Fall 2011 section:
This exarti has four questions and you are to work all of them. You must hand in your
paper by the end of class time (11:50am) unless prior arrangements have already been
mnade with the instructor.
You may tse a double-sided equation shéet. You are welcome to use your calculator and
an iftegral table.
In this exam, with the exception of the multiple-choice problems, you. must show all
your work to get credit. As a general rule, you must express your answers in terms of the
variables given. E.g., if'a variable Z is given, than the answer should be in terms of Z
and Hot £ or d.
Good luck!
Problem 1:
Problem 2:
Problem 3:
Problem 4:
Total:
Prebleni 1. (21 pts.)
(Multiplé Choice Questions, 3pts each, NO PARTIAL CREDIT)
CIRCLE the correct answer.
(1.1) A weight suspended from an ideal spring oscillates up and down. if the amplitude of
the oscillation is doubled, the period will
1 €!
fay emain the same. haa vei
‘B) double. ;
(C) halve. fs Lt?
bo
(D) ittercase by a factor of ¥2.
(E) decrease by a factor of V2. lily fe rpbed dle / /
(1.2) In sithple harmonic motion, the displacement is maximum whien:
(A) tlie acceleration is zero.
(B) the velocity is maximum.
(©pre velocity is zero.
(D) the kinetic energy is maximum.
(E) the momentum is maximum.
Problem 2. (20pts)
A thin ritig of mass Mand radilis Ris placed on a horizontal surface with an initial
angular velocity @,. The initial (translational) velocity of the center of mass of the ring is
zero. The kinetic frictional coefficient is 42 and the gravitational acceleration is g:
ie (ve) = a)
OF oe
a a —? Lr ze
: ie + = MR
How long does it take until the ring starts rolling without slippitig? (You must express
your answer in terms of the parameters given above.)
Me Ma ) Fy ofa Nilig
|
|
\y * air =x Fy i due a
i dt f ae? 2 ft ligk
7 i
ya f pf" Wg deo ab 4g B
ap
hl gt — (4@=e)
ee tt) wx ~ AEBS — eb FOL
Conthen Lo jplliny vurllout
“ f “ oo Ele v2 waster LMG
Up py obR Ue
= WI, ~ LE b
| OR
sage “Rabe )
JAG OE = R o2, ~g i
—~ 6M 7 OD
r
Reco LE : Tw -- Mg A Sue here, adel \
Problem 3. (20pts)
A pliysical pendulum consists of a thin solid disc of mass M and radius R with its
center attached to a thin rod of lengih 2R and negligible mass. The pendulum can rotate
freely in a vertical plane about an axis going through the other end of the rod. The
gravitational acceleration is g.
a
wlIF
SL Mee LMR
ger
2 Me
Z
What is the period of this pendulum for small oscillations? (Yott must express your
answer using the parameters given above.)
;
ue No f1g4 tar /
e
LO x Ligd ( Cag shiek WA L! 4 bs Caprei on /
Problem 4. (20pts)
Witli a solid metal block of volume V,, and density p,, we are trylitg to hold down (ina
tank of water) a plastic object of volume V, and density p, (they are connected by a
massless thin string). All objects are filly immersed iti water (which has
density 6, > p,) as illustrated below. The gravitational acceleraticti is g -
wudel bob:
Nmret 7 (9)
vba
Be t
(a) [iSpis] If the metal block stays at the bottom (as illustrated iri the figure), what is the
normal fotce N exerted by the bottom of the tank on the metal block? You must express
you answer in terms of Vy,, Py, Vp +» Pp» Py, andg.
mebl bbes ; M ~ fia G the Ya grt =- ©
pooh i “Ios g-T =°
Me - fa Yn Gothaba g -
[ve Qo “bey B+ (o~ Pao 9
pee é ce object :
(b) [Spts] ‘For given values of V,,, Vp, pp, and py, what is the minimum required
density of the metal block p;, so that it stays down at the bottom? You must express you
ansWer ititerms of Vy, V,, pp,and py.
[N>ef (is fle bey enol dant)
(hn fe) Via > foe fo) Up
fy a fot betel = pe