Physics 202A FIRST EXAM Chapters 1 - 3 Fall 2012
1
Name:_Answer Key
Solve the following problems in the space provided. Use the back of the page if needed. Each problem is
worth 20 points. You must show your work in a logical fashion starting with the correctly applied
physical principles. The equations you need are on the equation sheet. Your score will be maximized if
your work is easy to follow because partial credit will be awarded.
1. A baseball containing accelerometer,
speedometer and odometer is tossed straight
upward with an initial speed of 30m/s. Write in the
position, velocity, and acceleration reading that you
would expect at the end of each one-second
interval. Use coordinates where upward is positive.
To simplify the arithmetic use g=10m/s2. Notice
the decimal point before the last digit and the blue
boxes that contain a sign (±). If you want some
partial credit in the event that you make an
arithmetic mistake, explain how you are getting
your answers in the space below.
According to the Rule of Falling Bodies, the
acceleration remains a constant -10.0m/s2.
Therefore, the velocity will drop 10m/s every
second.
Using the definition of average speed, the distance
travelled is the average speed from t=0 until the
current time multiplied by the time.
a
x
v
a
x
v
a
x
v
a
x
v
a
x
v
a
x
v
t = 0s
t = 3s
t = 6s
t = 1s
t = 5s
t = 2s
t = 4s
a
x
v
+
1
0
0
0
0
0
0
3
+
-
+
4
5
0
2
0
0
-
0
0
+
1
2
0
-
0
1
0
-
0
1
0
-
0
1
0
-
0
1
0
-
0
1
0
-
0
0
0
+
2
0
0
+
1
0
0
+
0
0
1
0
0
-
-
3
5
0
+
2
5
0
+
4
0
0
+
4
0
0
+
