Download Moment of Inertia - Physics - Solved Paper and more Exams Physics in PDF only on Docsity! Calculate the net torque about point O for the two forces shown in the
figure. The rod and both forces are in the plane of the page. Take positive
torques to be counterclockwise.
) y= LON Py =8.00N
a) 12N-m .
b) -12 N-m
28 N-m
d) -28 N-m Eee
e) -52 N-m (e200 m—3ke—3.00 >|
Yet 12-smBo - 5-8
= 412 -4o
2 ~28 Nom
An artist constructs the perfectly-balanced mobile shown. If the artist
decides to make the star twice as massive, and not change the length of any
crossbar or the location of any object, what does she have to do with the
mass of the smiley face to keep the mobile in perfect balance? Note that
she may have to change masses of other objects to keep the entire structure
balanced.
a) make it eight times more mas-
sive
b) make it four times more mas-
sive
c} make it two times more mas-
sive
d) “nothing
e) impossible to tell
v
Smee geo aa rans the same, Ail masses
Most Che dle. Scevne. Backer,
3. ‘The flywheel of an engine has ee of inertia 3.0 kg-m* about its rotation
axis. What constant torque is required to bring it up to an angular speed
of 10 rad/s in 10s, starting from rest?
15N-m Ye a
3 Nem ust
Nem = vad |,
a) 30N-m a= 10 5 rad s®
e) 150N-m \Os
> Ts 3-4 2 3Nm
4. A 1.0 kg solid disc 0.5 m in radius is rolling without slipping on a horizontal
floor at a steady 2 rad/s. What is the total kinetic energy of the disc?
a)
4)
e)
0.5 J
TOT
1.25 J
1.5 J
KK TOTAL =
K Frans
+ KM yotetion
Vor
4 i 2
2 mye ttw
z 3™v * L
bomwtr?® 4
wr two 2 4 -(E)>@)? 22a
fiw Y
4-3 mer op ®
“5. A hoop, solid disc, and solid ball start from rest at the same fe hotht and roll
without slipping down the left part of the track shown. The right part of
the track is frictionless. Which object goes highest up the right side?
a)
b
d)
2)
hoop
solid di
solid ball
all of them clitnb to the same
height . :
it is impossible to determine
without knowing their diame-
ters ©
fons
"oy rere
a
é
}
x
f
A
°
oe
The obsect thar qoes Lnighest 3 Thee ene Wi, Fhe most
twans Natrere| /least sotenores\
the wk
6. A ‘Small (point-like plod on a Theme
Small
64 rahe
orizontal ohne
Newie-tic, energy ab botten, So
tok mWrha fms,
as & Mass
of 1 kg. It is attached to a massless cord passing through a hole in the
surface, as shown. The block at first revolves at a distance of 0.3 m from
“the hole with an angular speed of 1 rad/s. The cord is pulled from below,
shortening the radius of the circle in which the block revolves to 0.15 m.
What is the new angular-speed?
tLaels *
Lywy = Tg vg
lg THT met
xe om Ppp
a) 1 rad/s .
b) 2 rad/s > vad (c
4 d/s>
d) 8rad/s
8)
16 rad/s
