PoP5 Ex5.7mod
At what speed will a car negotiate a turn of radius r that is banked at an angle θ
above horizontal even when the road is so icy that the force of static friction is zero?
Walker4e
Two children ride on a merry-go-round, with child 1 at a greater distance from
the axis of rotation than child 2. The angular speed of child 1 is _____ the angular speed of
child 2.
A. greater than
B. less than
C. the same as Answer
PoP5 10.11b
A disk 8.00 cm in radius rotates at a constant rate of 1200 rev/min about its central axis.
What is the linear speed of a point 3.00 cm from its center?
A. 60 cm/s
B. 3.77 m/s
C. 10.5 m/s
D. 23.2 m/s Answer
PoP5 10.8
A centrifuge rotates at an angular speed of 3600 rev/min. When switched off, it rotates through
50.0 revolutions before coming to rest.
Find the constant angular acceleration α of the centrifuge.
A. −7.54 rad/s2
B. −1420 rad/s2
C. −377 rad/s2
D. −226 rad/s2 Answer
PoP5 OQ 10.08
Four particles are joined by light, rigid rods as shown. Assume a = b and M is larger
than m.
About which of the coordinate axes does the depicted system have the smallest and largest moment
of inertia?
A. Ix is smallest, Iy is largest.
B. Ix is smallest, Iz is largest.
C. Iz is smallest, Ix is largest.
D. Iy is smallest, Iz is largest. Answer
klm
What is the moment of inertia of System 2 as shown?
A. ½mR2
B. mR2
C. 2mR2
D. 4mR2 Answer
sb5 10.30
What is the moment of inertia of a solid sphere about an axis tangent to its surface?
A. 2MR2/5
B. 3MR2/5
C. MR2
D. 7MR2/5 Answer
Because the merry-go-round rotates as a single solid object, the
angular speed of every point on its surface is exactly the same. The linear speed of child 1,
however, is greater than the linear speed of child 2.
When the axis of rotation passes through a particle, that particle's
r is zero and it does not contribute to the moment of inertia. Therefore, Iz is
largest because all four masses contribute, and Ix is smallest because only the smaller
masses m contribute. In fact, Ix = 2ma²,
Iy = 2Ma², and
Iz = 2(m+M)a².