magalhaes (bam2734) – Homework #4 – Erskine – (58200)
1
This printout should have 26 questions.
Multiplechoice questions may continue on
the next column or page – fnd all choices
beFore answering.
001
10.0 points
A certain Force with units oF measure
M L
T
2
is
given by the equation
F
=
K M L
2
T
4
,
where
M
is a mass,
L
is a length,
T
is a time
and
K
is a constant.
What are units oF the constant
K
?
1.
[
K
] =
T
6
M
2
L
2
2.
[
K
] =
M
2
L
2
T
6
3.
[
K
] =
L
T
2
4.
[
K
] =
T
2
M L
5.
[
K
] =
T
2
L
correct
6.
[
K
] =
M L
T
2
Explanation:
Solving For
K
,
K
=
F T
4
M L
2
Since the dimensions oF Force are [
F
] =
M L
T
2
,
we get
[
K
] =
p
M L
T
2
P
T
4
M L
2
=
T
2
L
002
10.0 points
Despite a very strong wind, a tennis player
manages to hit a tennis ball with her racquet
so that the ball passes over the net and lands
in her opponent’s court.
Consider the Following Forces:
1. A downward Force oF gravity,
2. A Force by the hit, and
3. A Force exerted by the air.
Which oF the above Forces is (are) acting on
the tennis ball aFter it has leFt contact with
the racquet and beFore it touches the ground?
1.
1 and 3.
correct
2.
2 and 3.
3.
1, 2, and 3.
4.
1 and 2.
5.
1 only.
Explanation:
The Forces acting on the tennis ball aFter it
has leFt contact with the racquet are gravity
and air resistance. A Force by the hit is no
longer acting on the ball.
003
10.0 points
You place a box weighing 332
.
6 N on an in
clined plane that makes a 39
.
5
◦
angle with the
horizontal.
Compute the component oF the gravita
tional Force acting down the inclined plane.
Correct answer: 211
.
56 N.
Explanation:
Basic concepts
θ
W
θ
θ
W
W
1
The component oF the gravitational Force
acting down the plane is the side opposite the
angle
θ
, so
W
1
=
W
sin
θ
004
10.0 points
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Documentmagalhaes (bam2734) – Homework #4 – Erskine – (58200)
2
An object Q has a mass
M
Q
and an acceler
ation
va
Q
. Another object P of twice the mass
has twice the magnitude of acceleration in the
same direction as object Q.
What is true about
s
v
F
for object P
vs
object Q?
1.
s
v
F
P
has the same magnitude but op
posite direction from
s
v
F
Q
.
2.
s
v
F
P
has twice the magnitude of
s
v
F
Q
,
in the same direction.
3.
s
v
F
P
has four times the magnitude of
s
v
F
Q
, in the same direction.
correct
4.
s
v
F
P
has the same magnitude and di
rection as
s
v
F
Q
.
Explanation:
s
v
F
Q
=
M
Q
a
Q
and
s
v
F
P
= (2
M
Q
)(2
a
Q
) = 4
s
v
F
Q
.
005
10.0 points
Your friend says that inertia is a force that
keeps things in their places, either at rest or
motion.
Do you agree? Why or why not?
1.
Disagree; inertia is a property of matter
to behave this way, not some kind of force.
correct
2.
Agree; inertia is not a force that keeps
things moving.
3.
Disagree; inertia is a force that keeps
things moving.
4.
All are wrong.
5.
Agree; only forces can keep things in their
places.
Explanation:
Inertia is the property of things to resist
changes in motion.
This is the end of the preview.
Sign up
to
access the rest of the document.
 Spring '09
 erskine
 Force, Work, Correct Answer, Erskine

Click to edit the document details