(a) Identify the forces acting on the mass
m
1
. (Select all that apply.)
a
g

(b) Using the direction rosette indicate the direction for each of the forces acting on
m
1
that you
identified in part (a). If any of the forces listed below is not applicable, choose 'NA'.
Force
Direction
m
1
a
NA
NA
m
2
a
NA
NA
m
1
g
1
1
m
2
g
NA
NA
(
m
1
+
m
2
)
a
NA
NA
(
m
1
+
m
2
)
g
NA
NA
f
NA
NA
T
5
5
F
N
NA
NA
(c) Identify the forces acting on the mass
m
2
. (Select all that apply.)

a
g

(d) Using the direction rosette indicate the direction for each of the forces acting on
m
2
that you
identified in part (c). If any of the forces listed below is not applicable, choose 'NA'.
Force
Direction
m
1
a
NA
NA
m
2
a
NA
NA
m
1
g
NA
NA
m
2
g
1
1
(
m
1
+
m
2
)
a
NA
NA
(
m
1
+
m
2
)
g
NA
NA
f
NA
NA
T
5
5
F
N
NA
NA
(e) Write Newton's Second Law equation (in the form
F
net
=
ma
) for
m
1
in the
y
-direction. It is
important to use the correct signs for each of the forces. Motion in the upward direction is
positive and motion in the downward direction is negative. (Be sure to enter your answer in the
above form with the sum of the forces in the left hand side answer box. The right hand side
answer box should have the appropriate form of
ma
. Use the following as necessary:
a
,
f
,
F
N
,
m
1
, and
T
.)
g
,

(f) Write Newton's Second Law equation (in the form
F
net
=
ma
) for
m
2
in the
y
-direction. It is
important to use the correct signs for each of the forces. Motion in the upward direction is
positive and motion in the downward direction is negative. (Be sure to enter your answer in the
above form with the sum of the forces in the left hand side answer box. The right hand side
answer box should have the appropriate form of
ma
. Use the following as necessary:
a
,
f
,
F
N
,
m
2
, and
T
.)
g
,

(g) Use your answers from parts (e) and (f) to get an expression for the magnitude of the
tension
T
. (Use the following as necessary:
m
1
,
m
2
, and
g
.)

(h) Use your answers from parts (e), (f), and (g) to find the magnitude of
a
, the acceleration of
the system. (Use the following as necessary:
m
1
,
m
2
, and
g
.)

(i) In what direction will each mass accelerate?
up

(j) Suppose
m
1
=
8
kg and
m
2
=
12
kg. What is the tension in the string?

T
=
94.08 N
94.1 N
(k) Suppose
m
1
=
8
kg and
m
2
=
12
kg. What is the value of the acceleration?
a
=
1.96 m/s^2
1.96 m/s^2
(l) Suppose that
m
2
starts from rest at a height of
5
m. Use the kinematic equations to
determine how long it takes for
m
2
to hit the ground.
2.5 s
2.26 s
Additional Materials
Newton's Second Law
Appendix
6.
10/10 points |
Previous Answers
A bullet is shot into a block of plastic. The bullet penetrates the block
0.85
m. The mass of the bullet is
11
g. It is traveling with a speed of
525
m/s before it hits the block.
(a) Use kinematic equations to find the magnitude of the acceleration on the bullet as it is
penetrating the block (ignore gravity, and assume that the force on the bullet as it penetrates
the block is constant).

(b) Use Newton's Second Law to find the magnitude of the force exerted on the bullet by the
plastic block.

Additional Materials
Newton's Second Law
Appendix