truong (ajt2287) – HW#5 WorkEnergy – hester – (WVPHYSICSC2011)
1
This
printout
should
have
17
questions.
Multiplechoice questions may continue on
the next column or page – find all choices
before answering.
001
10.0points
Five ramps lead from the ground to the second
floor of a workshop, as sketched below.
All
five ramps have the same height; ramps B,
C, D and E have the same length; ramp A is
longer than the other four. You need to push
a heavy cart up to the second floor and you
may choose any one of the five ramps.
A
B
C
D
E
Assuming no frictional forces on the cart,
which ramp would require you to do the least
work?
1.
Ramp B.
2.
Same work for ramps B, C, D or E; more
work for ramp A.
3.
Same work for the straight ramps A and
B; less work for ramps C, D, and E.
4.
Unable to determine without knowing the
exact profiles of ramps C, D or E.
5.
Ramp C.
6.
Ramp D.
7.
Ramp E.
8.
Ramp A.
9.
Same work for all five ramps.
002
10.0points
A particle of mass
m
moves along the
x
axis.
Its position varies with time according to
x
=
(2 m
/
s
3
)
t
3
+ (

2 m
/
s
2
)
t
2
.
What is the work done by the force from
t
= 0 to
t
=
t
1
?
1.
W
= 2
m t
2
1
bracketleftBig
(144 m
/
s
6
)
t
2
1
+(

120 m
/
s
5
)
t
1
+ (25 m
/
s
4
)
bracketrightBig
2.
W
=
81
2
m t
2
1
bracketleftBig
(9 m
/
s
6
)
t
2
1
+(

12 m
/
s
5
)
t
1
+ (4 m
/
s
4
)
bracketrightBig
3.
W
= 2
m t
2
1
bracketleftBig
(9 m
/
s
6
)
t
2
1
+(

42 m
/
s
5
)
t
1
+ (49 m
/
s
4
)
bracketrightBig
4.
W
=
1
2
m t
2
1
bracketleftBig
(225 m
/
s
6
)
t
2
1
+(

480 m
/
s
5
)
t
1
+ (256 m
/
s
4
)
bracketrightBig
5.
W
=
81
2
m t
2
1
bracketleftBig
(1 m
/
s
6
)
t
2
1
+(

4 m
/
s
5
)
t
1
+ (4 m
/
s
4
)
bracketrightBig
6.
W
= 2
m t
2
1
bracketleftBig
(9 m
/
s
6
)
t
2
1
+(

12 m
/
s
5
)
t
1
+ (4 m
/
s
4
)
bracketrightBig
7.
W
= 8
m t
2
1
bracketleftBig
(9 m
/
s
6
)
t
2
1
+(

24 m
/
s
5
)
t
1
+ (16 m
/
s
4
)
bracketrightBig
8.
W
=
1
2
m t
2
1
bracketleftBig
(81 m
/
s
6
)
t
2
1
+(

252 m
/
s
5
)
t
1
+ (196 m
/
s
4
)
bracketrightBig
9.
W
=
25
2
m t
2
1
bracketleftBig
(9 m
/
s
6
)
t
2
1
+(

12 m
/
s
5
)
t
1
+ (4 m
/
s
4
)
bracketrightBig
10.
W
= 8
m t
2
1
bracketleftBig
(9 m
/
s
6
)
t
2
1
+(

12 m
/
s
5
)
t
1
+ (4 m
/
s
4
)
bracketrightBig
003(part1of2)10.0points
Given:
A block is pulled at a constant speed
along a horizontal surface by a rope with ten
sion
F
T
. The rope is inclined at an angle from
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
This is the end of the preview.
Sign up
to
access the rest of the document.
 Spring '11
 Steve
 Spanish, Force, Friction, Mass, Trường

Click to edit the document details