COMMON QUIZ 3 Physics 111 Version B QUIZ 3
A 500-kg sack of
coal is dropped on a 2000-kg railroad flatcar which was initially moving
at 3 m/s as shown. After the sack rests on the flatcar, the speed of the
flatcar is
0.6 m/s 1.2
m/s 1.8 m/s 2.4
m/s 3.6 m/s
A 3-gram bullet
is fired horizontally into a 10-kg block of wood suspended by a rope from
the ceiling. The block swings in an arc, rising 3 mm above its lowest position.
The kinetic energy of the block at the bottom of its swing is approximately:
0.3
J 0.0003 J
need to know how much heat was generated in the collision
zero 30 J
Blocks A and
B are moving toward each other. A has a mass of 2.0 kg and a velocity of
50 m/s, while B has a mass of 4.0 kg and a velocity of -25 m/s. They suffer
a completely inelastic collision. The kinetic energy dissipated during
the collision is:
0
2500 J 5000 J 7500
J 10000 J 3750
J
An elastic
collision is one in which:
momentum is not conserved but
kinetic energy is conserved
total mass is not conserved
but momentum is conserved
kinetic
energy and momentum are both conserved
momentum is conserved but kinetic
energy is not conserved
the total impulse is equal to
the change in kinetic energy
Block
A, with a mass of 2.0 kg, moves along the x axis with a velocity of 5.0
m/s (in the positive x direction). It suffers an elastic collision with
block B, which initially has a velocity of -2.0 m/s (in the negative x
direction). The blocks leave the collision along the x axis. If B is much
more massive than A, the velocity of A after the collision is:
0
-3.0 m/s -5.0 m/s
-7.0 m/s -9.0 m/s
Two
blocks (1 kg and 3 kg) are joined by a thread and travel together over
a horizontal frictionless surface at speed v as shown. The thread is then
cut. Their final speeds (V1 and V3) are
V1 = 2v/3, V 3 = v/3
V 1 = v/3, V 3 = 2v/3
V 1 = v/4, V 3 = 3v/4
V 1 = 3v/4, V 3 = v/4
none
of these
If a
wheel is turning at 3.0 rad/s, the time it takes to complete one revolution
is about: 0.33 s 0.67 s
1.0 s 1.3 s 2.1
s
A wheel
initially has an angular velocity of 18 rad/s but it is slowing at a rate
of 2.0 rad/s. By the time it stops it will have turned through:
13 rev 26 rev
39 rev 52 rev 65 rev
The figure shows a cylinder of radius 0.7 m rotating about its axis at 10 rad/s. The speed of the point P is
7.0 m/s
0.7 m/s none of these
Three identical balls are tied by light strings to the same rod and rotate
around it, as shown below. Rank the balls according to their rotational
inertia, least to greatest { 1,2,3} { 3,2,1}
{ 3, then 1 and 2 tie} { 1,3,2}
All are the same.
A certain
wheel has a rotational inertia of 12 kg m2. As it turns through
5.0 revolutions its angular velocity increases from 5.0 rad/s to 6.0 rad/s.
If the net torque is constant its value is:
0.016 Nm
0.18 Nm 0.57 Nm
1.1 Nm 3.6 Nm
2.1 Nm
A disk has a rotational inertia of 6.0 kgm2 and a constant angular acceleration of 2.0 rad/s2. If it starts from rest the work done during the first 5.0 s by the net torque acting on it is: 0 30 J 60 J 300 J 600 J