MCQs on Mechanical Actuating Systems – Preloading
1 - Question
What is the type of preload called when a bearing experiences a stress due to negative clearance?
a) Fastener preload
b) Bearing preload
c) Testing preload
d) Stress preload
View Answer
Explanation: When a bearing experiences a stress due to negative clearance then it is a type of bearing preload. These types of preload increases the bearing rigidity and helps in maintaining actual radial and axial position for displacement.
2 - Question
What is the strain on an object, when a force of 3 Newton is applied on it and it expands the length of the object from 4cm to 6 cm?
a) 2
b) 0.5
c) 1
d) 8
View Answer
Explanation: Given:- Force applied=3 N Original length(o)=4cm New length=6 cm Extended length(e)=New length-Original length Extended length(e)=6-4=>2cm Strain (s) = Extended length(e)/Original length(o) Strain (s)=2cm/4cm=>0.5.
3 - Question
What is the ratio of stress to strain called?
a) Youngs Modulus
b) Bulks Modulus
c) Modulus of elasticity
d) Modulus of rigidity
View Answer
Explanation: The ratio of stress to strain is called as Youngs Modulus. It is a mechanical property that measures the stiffness of a body. It establishes a relationship between stress and strain of a body. The youngs modulus graph or the stress-strain graph of a body showing elastic property is a straight line which shows the stress is proportional to strain. advertisement
4 - Question
What is the unit of stress?
a) Meter
b) Newton/Meter
c) Newton
d) Pascal
View Answer
Explanation: The unit of stress is Pascal. Stress is defined as the ratio of internal force of a material to resist deformation to the area of impact. Mathematically this gives out the unit as Newton/meter2 which is also termed as “Pascal”.
5 - Question
Pressure and stress are same as both are defined as force per unit area.
a) True
b) False
View Answer
Explanation: Pressure and stress are not same even if both are defined as force per unit area. The word “force” in pressure is the external force applied on a body, whereas “force” in the definition of stress refers to the internal force of a material to resist deformation.
6 - Question
Stress on a body occurs only when compressive force act on it.
a) True
b) False
View Answer
Explanation: Stress on a body occurs not only when compressive force act on it; but also when sheer or expanding forces are applied. Stress occurs on a body when any force is applied irrespective of the direction of the force.
7 - Question
What is the unit of strain?
a) Meter
b) Newton/Meter
c) Newton/Meter2
d) No unit
View Answer
Explanation: Strain has no unit. It is so because it is the ratio of two lengths. Strain is defines as the ratio of extended length of an object to its original length. Since both numerator and denominator have the unit of length, therefore they cancel out each other and thus strain has no unit.
8 - Question
What is the strain on a hook of a hanger, when its length expands from 5cm to 6 cm due to a hanging load?
a) 0.2
b) 0.5
c) 1.2
d) 0.3334
View Answer
Explanation: Given:- Original length(o)=5cm New length=6cm Extended length(e)=New length-Original length Extended length(e)=6-5=>1cm Strain (s) = Extended length(e)/Original length(o) Strain (s)=1cm/5cm=>0.2.
9 - Question
What is the value of stress that occurs on an object when a force of 5 Newton is applied perpendicularly to an area of 1meter2?
a) 2 Newton/meter2
b) 5 Newton/meter2
c) 1.2 Newton/meter2
d) 1 Newton/meter2
View Answer
Explanation: Given:- Force applied=5 N Area of impact=1meter2 Stress (S) = Force applied/Area of impact Stress (S) = 5 N/1meter 2=>5 N/meter2.
10 - Question
What is the strain on a hanging load, when a force of 1 Newton is applied on it and it expands the length of the object from 9cm to 12 cm?
a) 2
b) 0.5
c) 1.2
d) 0.3334
View Answer
Explanation: Given:- Force applied=1 N Original length(o)=9cm New length=12 cm Extended length(e)=New length-Original length Extended length(e)=12-9=>3cm Strain (s) = Extended length(e)/Original length(o) Strain (s)=3cm/9cm=>0.3334.
11 - Question
Preloads can avoid resonance due to external disturbances.
a) True
b) False
View Answer
Explanation: Preloads can avoid resonance due to external disturbances. These preloads can avoid harmful or the damage causing resonance by tensioning and increasing the natural frequency of the structure.
12 - Question
Pressure and stress both have same unit (i.e) “Pascal”.
a) True
b) False
View Answer
Explanation: Pressure and stress both have same unit (i.e) “Pascal”. The word “force” in pressure is the external force applied on a body, whereas “force” in the definition of stress refers to the internal force of a material to resist deformation. But mathematically they have same formula (i.e) Force/unit area which gives their units as Newton/meter2 or “Pascal”.
13 - Question
Sheer stress occurs when a body expands due to external force.
a) True
b) False
View Answer
Explanation: Sheer stress does not occur when a body expands due to external force. When a body expands due to external force it undergoes tensile stress. Sheer stress occurs when there is slippage along the plane parallel to the direction of imposed stress and a deformation in the shape of the object occurs.
14 - Question
What is the nature of the stress-strain graph of an elastic body?
a) Asymptotic
b) Linear
c) Parabolic
d) Non-Linear
View Answer
Explanation: The nature of the stress-strain graph of an elastic body is Linear. The youngs modulus graph or the stress-strain graph of a body showing elastic property is a straight line which shows the stress is proportional to strain.
15 - Question
What is the strain on a hanging load, when a force of 5 Newton is applied on it and it expands the length of the object from 8cm to 12 cm?
a) 2
b) 0.5
c) 1
d) 8
View Answer
Explanation: Given: Force applied=5 N Original length(o)=8cm New length=12 cm Extended length(e)=New length-Original length Extended length(e)=12-8=>4cm Strain (s) = Extended length(e)/Original length(o) Strain (s)=4cm/8cm=>0.5.