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Force and Moment of Force Quiz
 Forces
 Moments of Force
 Body Segment Parameters
 Mass
 Centre of Mass (or Gravity)
 Moments of Inertia
1. Which statement best defines
the moment of inertia?
a) Time immediately before a motion
starts.
b) Reluctance of a rigid body to linearly
accelerate.
c) Quantity of angular motion.
d) Resistance to change in angular
motion.
2. What’s the frictional force on the
20.0 kg box if the coefficient of kinetic
friction is 0.700? Assume the applied
force causes the object to be moving?
a) 196.2 N
b) 137.3 N
c) 20.0 N
d) 14.00 N
Fapplied
W = weight
Ffriction
Fnormal
3. What’s the acceleration of the 20 kg
box if the coefficient of kinetic friction
is 0.700 and the applied force is
300 N? Assume the object is moving.
a) 15.00 m/s2
b) 9.81 m/s2
c) 8.13 m/s2
d) 162.7 m/s2
Fapplied
W = weight
Ffriction
Fnormal
4. What is the angular acceleration caused by
a frictional force of 200 N on a runner whose
centre is 95.0 cm above a level runway if her
moment of inertia is 12.00 kg.m2? (Ignore the
vertical force.)
a) –16.67 rad/s2
b) –2400 rad/s2
c) –190.0 rad/s2
d) –15.83 rad/s2
Ffriction
5. What is the moment of inertia about
its centre of gravity of a 7.5 kg thigh if
the thigh’s length is 35 cm and its
radius of gyration is 50% of the length?
a) 0.230 kg.m2
b) 1.313 kg.m2
c) 2.63 kg.m2
d) 0.919 kg.m2
6. What happens when a resultant
force’s line of action passes through
the centre of gravity of a body?
a) object will continue
moving at constant velocity
b) object will accelerate in
the direction of the force
with no change in spin
c) object will accelerate
linearly and angularly
Correct answers
1)
2)
3)
4)
5)
6)
d
b
c
d
a
b
(resistance to ang. motion)
(=20.0 x 9.81 x 0.70)
(=300 – 137.3)
(=[200 x 0.95] /12)
(=7.5 x (0.35 x 0.50)2 )
(linear acceleration only)