PHYS2305: Practice Test 3
For the best result of the test, you need to understand completely the example problems in the lecture and the
homework problems. This practice test serves as a complementary tool. Please note that the actual test will not
necessary have the same questions as in this practice test. This practice test is to help you to study in
preparation of the upcoming test. DO NOT assume that there will be the same questions in the real test.
Use the following to answer questions 1-2:
A 4.0-kg block slides along a frictionless surface with a constant speed of 5.0 m/s as shown.
Two seconds
after
it begins sliding, a horizontal, time-dependent force is applied to the mass.
The force is removed eight seconds
later.
The graph shows how the force on the block varies with time.
1.
What is the magnitude of the total impulse of the force acting on the block?
A)
20 N
⋅
s
B)
42 N
⋅
s
C)
48 N
⋅
s
D)
54 N
⋅
s
E)
60 N
⋅
s
2.
What, approximately, is the speed of the block at
t
= 11 seconds?
3.
A sled of mass
m
is coasting on the icy surface of a frozen river.
While it is passing under a bridge, a
package of equal mass
m
is dropped straight down and lands on the sled (without causing any
damage).
The sled plus the added load then continue along the original line of motion.
How does the
kinetic energy of the sled + load compare with the original kinetic energy of the sled?
A)
It is 1/4 the original kinetic energy of the sled.
B)
It is 1/2 the original kinetic energy of the sled.
C)
It is 3/4 the original kinetic energy of the sled.
D)
It is the same as the original kinetic energy of the sled.
E)
It is twice the original kinetic energy of the sled.
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