1–15.
Two boys find that they can balance
each other on a plank if one sits
six feet from the fulcrum and the
other eight feet.
The heavier boy
weighs 120 pounds.
How much does
the lighter boy weigh?
1.
90 lb
2.
106 lb
3.
112 lb
4.
114 lb
1–16.
With the aid of
shown in figure
the
1D,
pipe wrench
how many pounds
of effort will you need to exert to
overcome a resistance of 900
pounds?
1.
25 lb
2.
50 lb
3.
75 lb
4.
100 lb
Questions 1-17 and 1–18 are related
o
to a 300–pound load of firebrick
stacked on a wheelbarrow.
Assume that the
weight of the firebrick is centered at a
point and the barrow axle is 1 1/2 feet
forward of the point.
1–17.
1-18.
1-19.
If a Seaman grips the barrow
handles at a distance of three feet
from the point, how many total
pounds will the Seaman have to lift
to move the barrow?
1.
65 lb
2.
100 lb
3.
150 lb
4.
300 lb
If a Seaman grasps the handles
3 1/2 feet from the point where the
weight is centered, how many pounds
of effort will be exerted?
1.
50 lb
2.
90 lb
3.
100 lb
4.
120 lb
In lever problems, the length of
the effort arm multiplied by the
effort is equal to the length of
the
1.
resistance arm multiplied by
the effort
2.
resistance arm multiplied by
the resistance
3.
effort arm multiplied by the
resistance arm
4.
effort arm multiplied by the
resistance
1-20.
The length of the effort arm in
figure 1E is equal to the length of
the
1.
curved line from A to C
2.
curved line from A to D
3.
straight line from B to C
4.
straight line from B to D
3
