PHYS 2001

1
PHYS 2001
Spring 2009

• Working Kinematics Problems
• Graphical Kinematics
• A. Using the Slope
• B. Using the Area Under the Curve

2
PHYS 2001
Spring 2009

• A car travels in the negative direction. If the
  car speeds up, its acceleration must be...?
• A. Positive B. Negative
• C. It cannot be determined

CT1
3
PHYS 2001
Spring 2009
EX1
A fighter jet lands on a carrier traveling at 140
m/s. The tailhook and wire provide an
acceleration to stop the jet whose magnitude is
70 m/s2. How long does it take the jet to stop?
4
PHYS 2001
Spring 2009
EX2
Two cars approach each other on a straight
stretch of highway. The first car is traveling
East at 25 m/s and the second car is traveling
West at 35 m/s. (a) If the cars are initially
400 m apart, how long does it take for the cars
to pass each other?
Two cars approach each other on a straight
stretch of highway. The first car is traveling
East at 25 m/s and the second car is traveling
West at 35 m/s. (b) How far have each of the
cars traveled when they pass each other?
5
PHYS 2001
Spring 2009
EX3
A hot air balloon takes off from the ground and
accelerates straight up at 0.71 m/s2. After 5
seconds, the balloonist drops a sandbag
overboard. How long does it take the sandbag to
hit the ground?
6
PHYS 2001
Spring 2009
CT2
Let up be the positive direction. When the
sandbag is dropped, the velocity of the sandbag
is...? A. Positive B. Negative C. Zero
Let up be the positive direction. When the
sandbag is dropped, the velocity of the balloon
is...? A. Positive B. Negative C. Zero
7
PHYS 2001
Spring 2009
EX3
A hot air balloon takes off from the ground and
accelerates straight up at 0.71 m/s2. After 5
seconds, the balloonist drops a sandbag
overboard. How long does it take the sandbag to
hit the ground?
8
PHYS 2001
Spring 2009
position (m)
time (s)
9
PHYS 2001
Spring 2009
velocity (m/s)
time (s)
10
PHYS 2001
Spring 2009
position (m)
time (s)
velocity (m/s)
time (s)
11
PHYS 2001
Spring 2009
A
B
C
D
E
F
CT3
In what region is the object moving in the
positive direction with a positive acceleration?
In what region is the object moving in the
negative direction with a negative acceleration?
In what region is the object moving in the
positive direction with a negative acceleration?
In what region is the object moving in the
negative direction with a positive acceleration?
12
PHYS 2001
Spring 2009
2
velocity (m/s)
time (s)
10
30
60
80
13
PHYS 2001
Spring 2009
10
velocity (m/s)
-5
time (s)
10
20
30
50
40