homework 07 – ARMSTRONG, DOMINIC – Due: Oct 23 2007, 3:00 am
1
Question 1, chap 10, sect 1.
part 1 of 1
10 points
An object having an initial momentum
that may be represented by the vector be
low strikes an object that is initially at rest.
Which of the following sets of vectors may
represent the momenta of the two objects af
ter the collision?
Note carefully:
The original vector above
and the following vectors are all drawn to the
same length scale.
1.
2.
3.
4.
correct
5.
6.
7.
Explanation:
There is no external force for the twoobject
system, so the total momentum is a constant.
From the choices, applying the vector sum
mation for the momenta of the two objects,
we can easily identify the correct choice.
The ±gure below shows the sum of the
x

and
y
components of the vectors which repre
sent the correct answer.
initial momentum
The horizontal vectors add to be the same
length as the vector presented in the question.
The vertical vectors cancel, as expected, since
there is no vertical momentum.
Question 2, chap 10, sect 1.
part 1 of 2
10 points
Two blocks,
A
and
B
, are connected by
a compressed spring. The mass of block
A
is twice that of block
B
. Immediately after
release, compare the net force on block
A
to the net force on block
B
.
The table is
frictionless and the mass of the spring is zero.
1.
F
B,net
will be in the opposite direction
and half as large as
F
A,net
.
2.
F
A,net
is equal in magnitude and direction
to
F
B,net
, and not zero.
3.
There is no net force on block
A
or block
B
.
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View Full Documenthomework 07 – ARMSTRONG, DOMINIC – Due: Oct 23 2007, 3:00 am
2
4.
F
A,net
is equal in magnitude and opposite
in direction to
F
B,net
, and not zero.
correct
5.
F
A,net
and
F
A,net
are both directed toward
the left with
F
A,net
larger than
F
A,net
, but not
twice as large. Block
A
is pulling block
B
.
6.
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 Fall '07
 Swinney
 mechanics, Force, Momentum, Work, total momentum, FB,net, DOMINIC

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