MIME 2300 Test 2
Name _______________________
April 7, 2008
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
!
1. a) If a force F is not zero, when does it do no work? (4 points)
Answer:
When it does not move or when it is perpendicular to path
b) Give two examples of conservative forces. (4 points)
Answer: weight and spring forces
c) Verbally define oblique central impact? (4 points)
Answer: Impact with one or more velocities not along line of impact
d) If
ϖ
= 4t
2
, what is
θ
? (4 points)
Answer:
c
3
t
4
c
dt
dt
d
3
+
=
+
ϖ
=
θ
ϖ
=
θ
∫
Page 1 of 4
1 __________/16
2 __________/25
3 __________/31
4 __________/28
Total ______/100
Key
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2. A 3500 kg car is traveling at 65 km/h on a horizontal road.
The driver then applies the brakes and the car
skids and hits a stationary wall 3 s later. The kinetic coefficient of friction between the tires and the road is 0.6.
(a) What is the speed of the car when it hits the wall? (9 pts)
(b) Assuming the car impacts the wall and fully stops within 0.01 s, find the magnitude of the average impact
force. (8 pts)
(c) Assuming the wall does not absorb much energy, what energy must the car bumper absorbs in order to
prevent damage of the car? (8 pts)
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 Spring '08
 Gan
 Force, Friction, Kinetic Energy, Mass, Velocity

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