Department of Natural Sciences
Clayton State University
February 14, 2014
Physics 2211 – Quiz 3
Name __SOLUTION___________________________________
1. An object is moving with constant non-zero acceleration along the +x-axis. A
graph of the velocity in the x direction as a function of time for this object is
a. a horizontal straight line.
b. a vertical straight line.
c. a parabolic curve.
d. a straight line making an angle with the time axis.
2. The acceleration of an object as a function of time is given by a(t) = (3.00
m/s3)t, where t is in seconds. If the object has a velocity 1.00 m/s at time t = 1.00
s, what is the displacement of the object between time t = 2.00 s and time t = 4.00
s?
a. 27.0 m
b. 36.0 m
c. 33.0 m
v(t )  (3 / 2t 2  1 / 2)m / s
x(t )  (1 / 3t 3  1 / 2t  C )m
x  x(4.00s)  x(2.00s)
3. Which figure could represent the velocity versus time graph of a motorcycle
whose speed is increasing? Circle one.
Graph # 3.
3. The position of an object as a function of time is given by x(t)=at3−bt2+ct−d,
where a=3.6 m/s3, b=4.0m/s2, c=60 m/s and d=7.0 m.
a. Find the instantaneous acceleration at t=2.4 s.
Vx  3at 2  2bt  c
a x  6at  2b
a x (t  2.4 s)  43.8 m / s 2
b. Find the average acceleration over the first 2.4 seconds.
a x , av 
V xf  V xi
t f  ti
Vxi  Vx (t  0)  60 m / s
Vxf  Vx (t  2.4 s)  103 m / s
a x,av  17.9 m / s 2