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1. (5
points)
Particle I is at position
r
1
at time
t=0
and it moves with a constant velocity
v
1
. Similarly, particle 2 is at position
r
2
at time
t=0
and moves with a constant velocity
v
2
. None of the vectors are equal. State a condition for which the particles will collide.
2. (5
points)
True or False: The frictional force acting on an object always has a direction
opposite to the object's velocity. Explain.
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View Full Document 3. (5 points) Identical constant forces push two identical masses A and B continuously from a
starting line to a finish line. If A is initially at rest and B is initially moving to the right,
which mass has the larger change in momentum? Explain.
4. (5
points)
Three identical ideal springs, each of spring constant k, are connected together
as shown. What is the effective spring constant of this combination (in terms of k)?
(a)
k/3
(b)
k/2
(c)
2k/3
(d)
k
(e)
3k/2
(f)
2k
(g)
3k
5. (5
points)
A child (Liz Carr, who will eventually become a physicist after recovering fully
from a nasty concussion, see below) is growing up in Maine, and the playground at her
school is frozen into a sheet of ice. She and her friends enjoy getting a running start from
opposite ends of the playground, and then sliding into each other. Suppose Liz has a mass of
20 kg, and a speed of 6
m/s,
and she collides at the angle shown with a friend of mass 30 kg,
moving at 4*sqrt(2)
m/s.
If they hold onto each other after the collision, whatis their
combined velocity?
6.
(5
points)
A twodimensional plate which has a uniform density per unit area is shaped
like a circle of radius 2 m
,
but it has a circular hole cut into it The hole has a radius of 1 m
and is centered at x = 1 m, y = 0. Where is the center of mass of the object?
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View Full Document 7. (5
points)
The movement of a particle is described by the polar coordinates
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This homework help was uploaded on 10/25/2007 for the course PHYS 1116 taught by Professor Elser, v during the Fall '05 term at Cornell University (Engineering School).
 Fall '05
 ELSER, V

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