10-40.
Which of the following chain
hoists has an efficiency of
85 percent?
1.
Screw gear
2.
Differential chain
3.
Spur gear
4.
Spindle gear
10–41.
The capacity of a winch may be
reduced by what percentage when
the last layer of wire rope is
being wound onto the winch drum?
1.
30%
2.
40%
3.
50%
4.
60%
10–42.
To avoid placing shock on a set of
slings, you should start a crane
lift quickly and smoothly.
1.
True
2.
False
Learning Objective:
Recognize the
principles of mixing and drilling
equipment.
10-43.
On a transit mixer, how many
revolutions of the drum at the
rate of rotation is usually
required to produce a specified
uniformity mix of concrete?
1.
10 to 40
2.
40 to 70
3.
70 to 100
4.
100 to 140
10-44.
Concrete, mixed in a transit
mixer, should be delivered within
1 1/2 hours or before the drum has
revolved a maximum of how many
times after the introduction of
water?
1.
100
2.
200
3.
300
4.
400
10-45.
A loaded
down for
keep the
transit mixer has been
more than an hour. To
concrete
inside the truck,
total of how many
to the concrete?
1.
2 pounds
2.
5 pounds
3.
10 pounds
4.
15 pounds
from setting up
you should add a
pounds of sugar
10–46.
The crete mobile carries which of
the following ingredients in
divided bins mounted on the unit?
1.
Cement
2.
Sand
3.
Coarse aggregates
4.
All of the above
10–47.
The mixing action of a crete
mobile is a continuous process
that can proceed until the
aggregate bins are empty.
1.
True
2.
False
10-48.
To keep an earth auger from
bouncing, when working in hardpan
or rocky soil, an operator should
take what action.
1.
Increase the engine rpm
2.
Slip the clutch
3.
Use support jacks
4.
Increase the air pressure
in the tires
10-49.
To clean the drilling components
of dirt when raising the auger bit
from a drilling hole, you should
take which of the following
actions?
1.
Increase the drill rpm
2.
Lower the engine speed
3.
Tilt the auger fore and aft
while the engine is running
4.
Tilt the auger fore and aft
while slowly pulling the bit
out of the hole
75
