@ Avril Slone 2008
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EG-260 Dynamics 1
Pre-course Revision Questions
1.
a.
State what is meant by
angular velocity.
b.
A stone is tied to one end of a cord and rotated in a
horizontal circle about a point C with the cord horizontal,
as shown in Figure 1. The stone has speed
v
and angular
velocity
w
about C. The length of the cord is
r.
i.
Write down the relationship between the speed
v
, the
length of cord
r
and the angular velocity
w.
ii.
Explain how
v
can be made to vary when
w
is constant.
iii.
Explain why there needs to be tension in the cord to
maintain the circular motion.
iv.
Write down an expression for the acceleration of the stone
in terms if
v
and
r.
Hence, if the stone has mass
m
, show that the tension in the
cord, T is given by:
w
mv
T
=
c.
On one particular ride in an amusement park, passengers
‘loop-the loop’ in a vertical circle, seen in
Figure 2
The loop has a radius of 7.0m and a passenger, mass 60 kg,
is travelling at 12 ms
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