(
29
(
29
33
.
1
100
3
F
0
avg
=
+
MIME 2300 Test 2
Name _______________________
July 17, 2006
In all the problems show all equations used with variables and then with values substituted so partial
credit can be given wherever possible.
Give units on all answers and write only in the space provided.
On problems where appropriate, draw coordinate systems, datums, FBDs, K.Ds or velocity diagrams.
Do not use F=ma as the primary method to solve any problems on this test
!
1a. Give two examples of conservative forces and two examples of nonconservative forces. (4 points)
* Springs and gravity
* Friction and any applied force besides springs and gravity
1b. Define impulsive forces and discuss why they are important. (4 points)
* Large forces compared to other forces acting over a short amount of time
* Permit application of conservation of momentum
2. A battery powered winch attached to a cart C pulls a 200 kg box B to the left over the smooth cart.
The mass
of cart, wheels, winch and battery, excluding the box, is 100 kg.
Three seconds after starting from rest, the box
has a speed of 2 m/s relative to the cart.
For this time interval, determine (a) the final velocity of the cart and
(b) the average cable tension.
Ignore the size of the wheels.
(19 points)
Solution:
Coordinate system
2
B
B
2
C
C
1
B
B
1
C
C
v
m
v
m
v
m
v
m
+
=
+
2
v
v
2
C
2
B

=
(
29
2
v
200
v
100
0
0
2
C
2
C

+
=
+
400
v
300
0
2
C

=
s
/
m
33
.
1
v
2
C
=
∫
=
+
3
0
2
C
C
avg
1
C
C
v
m
dt
F
v
m
N
4
.
44
F
avg
=
Page 1 of 4
1 __________/8
2 __________/19
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 Spring '08
 Gan
 Force, Friction, Coordinate system, rDB u DB

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