MACHINES
1.
A machine
is required to raise a load of 100N with an applied force of 10N. what is the mechanical advantage?
a)
1000N
b)
100N
c)
10N
d)
1N
2.
A machine
is required to raise a load of 50N with an applied force of 0.5N. what is the mechanical advantage?
a)
25N
b)
2.5N
c)
55.5N
d)
100N
3.
A machine
of velocity 0.5 has a mechanical advantage of?
c)
2
4.
Which of
this is the correct expression for an inclined plane?
a)
c)
cot
d)
tan
5.
which of the
following statements about machine is not correct?
a)
It is a
device for doing work more conveniently
b)
All machines are made of gear, wheel, levers,
pulleys and screw
c)
A machine
often does work faster than man
d)
A fishing
rod is a machine
6.
Which of the following definition about simple
machine is not correct?
a)
Velocity
ration is effort/load
b)
Mechanical
advantage is load/effort
c)
Efficiency
is mechanical advantage/velocity ratio
d)
Work input is product of load and distance
moved by the load
7.
Which of
the following statements defines correctly the efficiency of a machine?
a)
The load
carried by the machine divided by the effort required in carrying the load
b)
The
distance moved by the load divided by the distance moved by the effort
c)
The useful workdone
by the machine divided by the total work put into it
d)
All of the
above
8.
In
practice, a machine can never be 100% efficient. This statement implies that?
a)
The
mechanical advantage of a machine is always less than 1
b)
The
velocity ratio of a machine is always more than 1
c)
The
velocity ratio of a machine is never greater than the mechanical advantage
d)
The useful work obtained from a machine is
always less than the workdone by it.
9.
What is
the relationship between mechanical advantage and load?
a)
M.A 
b)
M.A 
L
c)
L
d)
M.A 
L
10.
What is
the relationship between velocity ratio and load?
a)
V.R 
b)
V.R L
c)
L
d)
V.R L
11.
What is
the relationship between mechanical advantage and velocity ratio?
a)
M V
b)
M V
c)
M 
d)
M 
12.
A machine
has a velocity ratio of 5. It requires a 50kg weight to overcome a 200kg
weight. The efficiency is?
a)
4%
b)
6%
c)
40%
d)
80%
13.
A machine
has a velocity ratio of 4, it requires 800N to
overcome a load of 1600N. what is the efficiency of
the machine?
a)
2%
b)
40%
c)
50%
d)
60%
14.
What
effort will a machine of efficiency 90% apply to lift a load of 180N if its
effort arm is twice as long as its load arm?
a)
90N
b)
100N
c)
120N
d)
80N
15.
What
effort should be exerted to lift a load of 150N with a machine having velocity
ratio of 3 and an efficiency of 20%?
a)
750N
b)
500N
c)
250N
d)
450N
16.
A machine
requires 1000J of work to raise a load of 500N through a vertical distance of
1.5m. calculate the efficiency of the machine.
a)
80%
b)
75%
c)
50%
d)
33%
17.
The
velocity ratio of a machine is 5 and its efficiency is 75%. What effort would
be needed to lift a load of 150N with the machine?
a)
20N
b)
30N
c)
40N
d)
50N
18.
A simple
machine with an efficiency of 75% lifts a load of 5000N when a force of 500N is
applied to it. Calculate the velocity ratio of the machine.
a)
10.0
b)
13.3
c)
17.3
d)
25.0
19.
A machine
has an efficiency of 80%. If the machine is required to overcome a load of 60N
with a force of 40N, calculate its velocity ratio.
a)
0.53
b)
0.83
c)
1.20
d)
1.88
20.
In which
of the following simple machine is the effort applied between the load and the
fulcrum?
a)
Claw
hammer
b)
Pliers
c)
Wheel
barrows
d)
Sugar tong
21.
Which of
these is a third class lever?
a)
Sugar tong
b)
Bottle
opener
c)
Table
knife
d)
All of the above
22.
Which of
the following machines does not apply the lever principle?
a)
Claw
hammer
b)
Wheel
barrow
c)
Single moving pulley
d)
Nut
cracker
23.
Which of
the following lever is not in the same class as the others in respect to the
location of the load, effort and the frlcrum?
a)
Sugar tong
b)
Scissors
c)
Pincers
d)
See-saw
24.
Which of
the following instrument in its normal use serves as a first class lever?
a)
Pair of scissors
b)
A pair of
sugar tong
c)
A bottle
opener
d)
A knife
25.
At what
distance from the fulcrum will a boy of mass 40kg balance another boy of mass
60kg who is sitting 5.0m from the fulcrum on the other side?
a)
1.5m
b)
3.3m
c)
4.0m
d)
7.5m
26.
A load of
mass 5kg is being lifted vertically upwards by a frictionless pulley. If the
system is 80% efficient, calculate the value of the applied effort.
a)
80N
b)
60N
c)
62.5N
d)
6.3N
27.
It is more
convenient to use a lever when the?
a)
Effort is
closer to the fulcrum than the load
b)
Load and
the effort are at same distance from the fulcrum
c)
Effort is
almost at the same distance from the fulcrum
d)
Load is closer to the fulcrum than the effort.
28.
A block and tackle is used to raise a load of
250N through a vertical distance of 30m.what is the efficiency of the system if
the workdone against friction is 1500J?
a)
62.5%
b)
73.3%
c)
83.3%
d)
94.3%
29.
What is
the velocity ratio of a pulley system having three pulleys in the fixed block
and two in the movable block?
a)
2
b)
3
c)
4
d)
5
30.
A block
and tackle is used to raise a load of 20N through a vertical height of 10m. if the efficiency is 40%, how much work is done against
friction?
a)
80J
b)
120J
c)
300J
d)
500J
31.
Lubricants
used in machines to reduce friction
a)
Decrease
the MA
b)
Increase the MA
c)
Decrease
the VR
d)
Increase
the VR
32.
Which of
the following actions will improve the efficiency of a pulley system?
a)
Reducing the mass of the pulley
b)
Increasing
the mass per unit length of the string of the pulley
c)
Increasing
the frictional force between the string and the pulley
d)
Increasing
the mass of the pulley
33.
The
mechanical advantage of an inclined plane depends on
a)
Its length
b)
Its height
c)
The
product of its length and height
d)
The ratio of its length to its height
34.
An
inclined plane of angle , acting as a simple machine has a velocity ratio
a)
c)
sin
d)
sin cos
35.
An
inclined plane which makes an angle of 30o with the horizontal has a
velocity ratio of?
a)
2
b)
1
c)
0.8660
d)
0.50
36.
What is
the velocity ratio of an inclined plane of length 2.6m, vertical height above
the ground 1.3m, and angle of inclination to the horizontal 30o?
a)
2.0
b)
1.3
c)
1.15
d)
0.577
37.
A 20kg
mass is to be pulled up a slope inclined at 30o. if
the efficiency of the plane is 75%, the force required to pull the load up the
plane is? (g=10ms-2)
a)
13.3N
b)
73.3N
c)
133.3N
d)
533.2N
38.
A particle
of weight 120N is placed on a plane inclined at an angle 30o to the
horizontal. If the plane has an efficiency of 60%, what is the force required to push the weight uniformly up the plane?
a)
210N
b)
175N
c)
100N
d)
50N
39.
Gear
wheels are used in machines for varying I. mechanical advantage II. Speed III. velocity
ratio
a)
I & II
only
b)
II & III only
c)
I &
III only
d)
I, II
& III
40.
A wheel and axle have
radii 80cm and 10cm respectively, if the efficiency of the machine is 0.85, an
applied force of 1200N will raise a load of?
a)
8.0N
b)
6.8N
c)
81.60N
d)
9600N
41.
A 20-
toothed gear wheel drives a 60- toothed one. If the angular speed of the
smaller wheel is 120revs-1, the angular speed of the larger wheel
is?
a)
3revs-1
b)
40 revs-1
c)
360 revs-1
d)
2400 revs-1
42.
The pitch
of a screw jack is 0.45cm and the arm is 60cm long. If the efficiency of the
jack is 
,
calculate the mechanical advantage.
a)
400
b)
300
c)
200
d)
150
43.
Calculate
the velocity ratio of a screw jack of pitch 0.3cm if the length of the tommy
bar is 21cm.
b)
14
c)
70
d)
140
44.
A spanner
of length 20cm is used to turn a nut. If the spanner were replaced by another
of length 15cm and held at its end with the same effort as in the first case,the
a)
Velocity ratio would decrease
b)
Velocity ratio
would increase
c)
Mechanical
advantage would decrease but the velocity ratio would remain constant
d)
Mechanical
advantage would increase but the velocity ratio would remain constant
45.
Which of these statement is correct about a screw jack used in
raising a car?
a)
Velocity ratio
= pitch of screw /2
x length of the effort handle
b)
Mechanical advantage
= effort applied/weight of car
c)
Velocity ratio can be increased by using a jack with a
smaller pitch
d)
Velocity ratio
can be decreased by increasing the length of the effort arm
46.
The distance through
which a screw jack moves along its head when the screw head is turned through
180o is
a)
Half the pitch
b)
The pitch
c)
One and half the
pitch
d)
Twice the pitch
47.
In a
hydraulic press
a)
A small
downward force on the smaller piston produces a large downward force on the
larger piston
b)
A large
upward force on the smaller piston produces a large upward force on the larger
piston
c)
A small
upward force on the smaller piston produces a small upward force on the larger
piston
d)
A small downward force on the smaller piston
produces a large upward force on the larger piston
48.
The area of the effort and load pistons of a hydraulic press are
0.5m2 and 5m2 respectively. If a force F1(100N)
is applied on the effort piston, the force F2 on the load is
a)
10N
b)
1000N
c)
500N
d)
5000N
49.
In a
hydraulic press, the pump piston exerts a pressure 100PA on the liquid. What force
is exerted in the second piston of cross sectional area 3m2
a)
200N
b)
150N
c)
100N
d)
300N
50.
A
hydraulic press has a large circular piston of radius 0.8m and a circular plunger.
Find the force exerted by the piston.
a)
8000N
b)
4000N
c)
2000N
d)
1000N
51.
In a small
hydraulic press, the diameters of the effort plunger and the load plunger are
1cm to 10cm respectively. Find the effort needed to raise a load of 1500N, and
the pressure inside the apparatus while this is being done.
a)
15N,
760N/m2
b)
15000N, 1.9
x 105N/m2
c)
15N, 1.9 x
105N/m2
d)
1500N,
760N/m2
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