Ch8_1
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Make sure to calculate your answers in SI units unless specified otherwise .
1) A disk turns with an average angular velocity of
rad/s
. Through which angle in
degrees
does the disk turn in
sec
(see sheet 3)
? Indicate with a negative (positive) sign whether a point on the disk at larger distance
r
from the center of rotation moves faster (slower) than a point at smaller distance
r
from the center.
2) A point marked at the edge of a rotating disk which has a radius of
cm
moves a distance of
m
in
minutes
. What is the average angular velocity of the disk (in
SI
units)
(see sheet 4)
? Indicate with a negative (positive) sign whether you can (cannot) use the same expression you used above to relate the instantaneous angular velocity and the instantaneous tangential velocity to each other.
3) A wheel with a
meter
radius, initially at rest, rolls down an incline and reaches after
seconds
a linear velocity of
m/s
. What is the angular acceleration of the wheel
(see sheet 5
and the beginning of
34
where rolling is explained) ? Indicate with a positive (negative) sign whether the tangential velocity of a point on the rim of the wheel is the same as (different from) the linear velocity of the wheel.
4) The constant tangential acceleration of a point at the edge of a rotating disk with a
cm
radius is
m/s
2
. If the disk starts out with
rpm
(see sheet 10 for "rpm")
what is the angular velocity after 4
seconds
(see sheet 5,7,10)
? Indicate with a positive (negative) sign whether the initial angular velocity is (is not) given in
SI
units.
5) A wheel starts out at rest and makes revolutions under a constant angular acceleration of
rad/s
2
. It then stops abruptly. How long was the wheel in motion
(see sheet 11)
? Indicate with a negative (positive) sign whether the angle through which the wheel turns is (is not) given in
SI
units.
6) A disk under a constant angular acceleration of
rad/s
2
increases its initial angular velocity of
rads/s
by a factor . Through how many
radians
does the wheel turn
(see sheet 7)
?
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cannot resubmit answers
for the same Problem Set--you must use the 'New Problems' button first.