1.
The unit of force in S.I. units is
Correct Answer
B. Newton
Explanation
The unit of force in S.I. units is newton. The newton is defined as the amount of force required to accelerate a one-kilogram mass by one meter per second squared. It is named after Sir Isaac Newton, who made significant contributions to the field of physics and formulated the laws of motion. The newton is widely used in scientific and engineering applications to measure forces such as weight, tension, and friction.
2.
Which of the following is not the unit of power ?
Correct Answer
D. Kcal/kg sec
Explanation
The unit "kcal/kg sec" is not a unit of power. It is a unit of specific heat capacity, which measures the amount of heat required to raise the temperature of a unit mass of a substance by one degree Celsius. Power, on the other hand, is the rate at which work is done or energy is transferred. The correct units of power in the given options are kW (kilowatt) and hp (horse power).
3.
Which of the following is not a scalar quantity.?
Correct Answer
C. Acceleration
Explanation
Acceleration is not a scalar quantity because it has both magnitude and direction. Scalar quantities only have magnitude and no direction. Time, mass, volume, and density are all scalar quantities as they only have magnitude and no specific direction associated with them.
4.
Which of the following is a vector quantity.?
Correct Answer
B. Momentum
Explanation
Momentum is a vector quantity because it has both magnitude and direction. It is defined as the product of an object's mass and velocity, and its direction is the same as the direction of its velocity. This means that momentum can be positive or negative, depending on the direction of the object's motion. In contrast, energy, angle, and speed are scalar quantities as they only have magnitude and no specific direction associated with them.
5.
The C.G. of a plane lamina will not be at its geometrical centre in the case of a
Correct Answer
A. Right angled triangle
Explanation
The correct answer is a right angled triangle. In a right angled triangle, the centroid (C.G.) does not coincide with the geometrical center. The centroid is the point where the medians of the triangle intersect, and in a right angled triangle, the centroid is located at one-third of the distance from the right angle to the midpoint of the hypotenuse. Therefore, the C.G. of a right angled triangle is not at its geometrical center.
6.
The algebraic sum of moments of the forces forming couple about any point in their plane is
Correct Answer
A. Equal to the moment of the couple
Explanation
The algebraic sum of moments of the forces forming a couple about any point in their plane is equal to the moment of the couple. This means that when calculating the total moment of the forces in a couple, regardless of the point chosen, the result will always be equal to the moment of the couple. This is because the forces in a couple are equal in magnitude, opposite in direction, and have parallel lines of action, resulting in a net moment of zero. Therefore, the sum of the moments of the forces forming the couple will always be equal to the moment of the couple itself.
7.
The locus of the instantaneous centre of a moving rigid body, is
Correct Answer
C. Centroid
Explanation
The correct answer is centroid. The locus of the instantaneous center of a moving rigid body is the centroid. The centroid is the point where all the mass of the object is concentrated, and it remains fixed during the motion of the body. It is the average position of all the points in the body and is often used to analyze the motion and stability of the object.
8.
The forces which meet at one point and have their lines of action in different planes are called
Correct Answer
B. Non-coplaner concurrent forces
Explanation
Non-coplaner concurrent forces refer to forces that do not lie on the same plane and meet at a single point. These forces have different lines of action, meaning they act along different directions. This type of force system can result in the rotation or translation of an object depending on the magnitude and direction of the forces involved.
9.
The unit of Moment of Inertia of a body, is
Correct Answer
D. M4
Explanation
The unit of Moment of Inertia of a body is m^4. This is because Moment of Inertia is calculated by multiplying the mass of an object by the square of its distance from the axis of rotation. Since mass is measured in kilograms (kg) and distance is measured in meters (m), when we square the distance, it becomes m^2. Therefore, when we multiply kg by m^2, the unit of Moment of Inertia becomes m^4.
10.
The Law of Polygon of Forces states that
Correct Answer
C. If forces acting on a point can be represented of a polygon taken in order, their sides of a polygon taken in order, their resultant will be represented in magnitude and direction by the closing side of the polygon, taken in opposite order
Explanation
The Law of Polygon of Forces states that if forces acting on a point can be represented by the sides of a polygon taken in order, then their resultant will be represented in magnitude and direction by the closing side of the polygon, taken in opposite order. This means that if we draw a polygon with the sides representing the forces in magnitude and direction, the closing side of the polygon, taken in opposite order, will represent the resultant force. This is because the resultant force is the force needed to balance out all the other forces acting on the point.
11.
Work may be defined as
Correct Answer
A. Force x distance
Explanation
Work is defined as the product of force and distance. This means that work is done when a force is applied to an object and it causes the object to move a certain distance. The amount of work done is directly proportional to both the force applied and the distance over which the force is applied. Therefore, the correct answer is force x distance.
12.
Lami's theroem states that
Correct Answer
C. Three coplaner forces acting at a point will be in equilibrium, if each force is proportional to the sine of the angle between the other two
Explanation
Lami's theorem states that three coplanar forces acting at a point will be in equilibrium if each force is proportional to the sine of the angle between the other two. This means that if the magnitudes and directions of the three forces can be represented by the sides of a triangle, then the point will be in a state of equilibrium. This theorem helps to analyze and understand the balance of forces acting on a point, allowing for the determination of whether the forces will cancel each other out or result in a net force.
13.
If two forces acting at a point are in equilibrium, they must be equal in magnitude and their line of action must be along
Correct Answer
B. The same line in opposite sense
Explanation
If two forces acting at a point are in equilibrium, it means that the forces are balanced and cancel each other out. In order for this to happen, the forces must have equal magnitudes but act in opposite directions. This is because if the forces were in the same direction, they would add up and not be balanced. Therefore, the line of action for the forces must be along the same line, but in opposite senses.
14.
The characteristic of a couple, is
Correct Answer
E. All the above.
Explanation
The correct answer is "all the above." This is because all of the statements provided in the answer options are true characteristics of a couple. A couple is formed by two equal and opposite forces that create a rotational effect without any translational motion. The algebraic sum of the forces constituting a couple is zero, meaning they cancel each other out. The algebraic sum of the moments of the forces about any point is the same, indicating that the rotational effect is consistent. A couple can only be balanced by another couple of opposite sense, and it cannot be balanced by a single force. Therefore, all of the statements mentioned in the answer options are correct characteristics of a couple.
15.
Three forces which act on a rigid body to keep it in equilibrium. The forces must be coplanar and
Correct Answer
A. Concurrent
Explanation
The correct answer is "concurrent" because in order for a rigid body to be in equilibrium, the three forces acting on it must meet at a single point, known as the point of concurrency. This means that the forces have to have the same line of action and pass through a common point. If the forces were parallel or not concurrent, they would create a net torque on the body, causing it to rotate and not be in equilibrium.
16.
Newtons's Law of Motion is
Correct Answer
D. All the above
Explanation
The given answer, "All the above," is correct because it includes all three statements of Newton's Law of Motion. The first statement, known as the law of inertia, states that an object will remain at rest or in uniform motion unless acted upon by an external force. The second statement describes how the rate of change of momentum is proportional to the applied force. The third statement states that for every action, there is an equal and opposite reaction. Therefore, all three statements are part of Newton's Law of Motion.
17.
Pick up the incorrect statement from the following :
Correct Answer
D. The C.G. of a semicircle is at a distance of r/2 from the centre
Explanation
The incorrect statement is "The C.G. of a semicircle is at a distance of r/2 from the centre." The correct statement is that the C.G. of a semicircle is at a distance of 4r/3Ï€ from the center. This is because the C.G. of a semicircle is located along the diameter, one-third of the way from the center to the circumference.
18.
Energy may be defined as
Correct Answer
B. Capacity of doing work
Explanation
Energy can be defined as the capacity of doing work. This definition implies that energy is the ability or potential to perform a task or exert a force to accomplish a certain amount of work. It encompasses the idea that energy is stored within a system and can be converted into different forms to accomplish various types of work. Therefore, the statement "capacity of doing work" accurately describes the concept of energy.
19.
The centre of gravity of a homogenous body is the point at which the whole
Correct Answer
C. Weight of the body is assumed to be concentrated
Explanation
The correct answer is "weight of the body is assumed to be concentrated." The center of gravity of a homogeneous body is the point where the entire weight of the body can be considered to be concentrated. This point represents the average position of the weight distribution within the body.
20.
Centre of gravity of a thin hollow cone lies on the axis of symmmetry at a height of
Correct Answer
B. One-third of the total height above base
Explanation
The center of gravity of a thin hollow cone lies one-third of the total height above the base. This is because the center of gravity of any object is the point where its weight is considered to act. In the case of a cone, the weight is distributed uniformly along its height. Since the cone is hollow, the weight is concentrated towards the outer surface. As a result, the center of gravity is shifted towards the top of the cone, specifically one-third of the total height above the base.
21.
The unit of moments in M.K.S system, is
Correct Answer
A. Kg-m
Explanation
In the MKS system, the unit of moments is represented by kg-m. This unit is derived from multiplying the unit of mass (kg) by the unit of distance (m). Moments are a measure of the turning effect or torque produced by a force acting on an object. The unit kg-m indicates that the moment is equal to the product of a mass in kilograms and a distance in meters.
22.
A point subjected to a number of forces will be in equilibrium, if
Correct Answer
A. Sum of resolved parts in any two directions at right angles, are both zero
Explanation
The explanation for the correct answer is that if the sum of resolved parts in any two directions at right angles is both zero, it means that the forces acting on the point are balanced. This is because the resolved parts of the forces cancel each other out in both directions, resulting in no net force acting on the point. Therefore, the point will be in equilibrium, meaning it will not experience any acceleration or movement.
23.
If the shear force along a section of a beam is zero, the bending moment at the section is
Correct Answer
B. Maximum
Explanation
If the shear force along a section of a beam is zero, it means that there is no external force acting perpendicular to the section. In such a case, the bending moment at the section would be at its maximum. This is because the bending moment is directly proportional to the shear force, and when the shear force is zero, the bending moment is at its highest value.
24.
The shape of the bending moment diagram over the length of a beam, carrying a uniformly distributed load is always
Correct Answer
B. Parabolic
Explanation
The shape of the bending moment diagram over the length of a beam carrying a uniformly distributed load is always parabolic. This is because the bending moment is directly proportional to the product of the load and the distance from the point of interest. In the case of a uniformly distributed load, the load is constant over the entire length of the beam. As a result, the bending moment increases linearly with the distance from the support, resulting in a parabolic shape for the bending moment diagram.
25.
For a simply supported beam with a central load, the bending moment is
Correct Answer
D. Maximum at the centre
Explanation
The bending moment in a simply supported beam with a central load is maximum at the center. This is because the load at the center causes the beam to bend downwards, creating a moment that is highest at the midpoint. As the distance from the center increases towards the supports, the bending moment decreases. At the supports, the bending moment is least or zero, as the beam is fixed and cannot bend further.
26.
The number of points of contraflexure in a simple supported beam carrying uniformly distributed load, is
Correct Answer
D. 0
Explanation
A simple supported beam carrying a uniformly distributed load does not have any points of contraflexure. Contraflexure occurs in a beam when the bending moment changes sign from positive to negative or vice versa. However, in a simple supported beam with a uniformly distributed load, the bending moment remains constant and does not change sign, resulting in no points of contraflexure.
27.
A bending moment may be defined as :
Correct Answer
C. Algebraic sum of the moments of all the forces on either side of the section
Explanation
The correct answer is the algebraic sum of the moments of all the forces on either side of the section. This means that the bending moment is calculated by taking into account the direction and magnitude of each force on either side of the section and summing up their moments. The algebraic sum takes into consideration the signs of the moments, which can be either positive or negative depending on the direction of the force. By considering the moments of all the forces, we can determine the bending moment at a specific section of a structure.
28.
The moment diagram for a cantilever carrying a concentrated load at its free end, will be
Correct Answer
A. Triangle
Explanation
The moment diagram for a cantilever carrying a concentrated load at its free end will be a triangle. This is because the moment is zero at the fixed end of the cantilever and increases linearly towards the free end where the load is applied. The shape of a triangle represents this linear increase in moment.
29.
The bending moment is maximum on a section where shearing force
Correct Answer
D. Changes sign
Explanation
The bending moment is maximum on a section where the shearing force changes sign. This is because when the shearing force changes sign, it indicates a shift in the direction of the applied forces on the section. This change in direction causes a moment to be generated, resulting in a maximum bending moment.
30.
Reactions at the supports of a structure can be determined by equating the algebraic sum of
Correct Answer
D. All the above.
Explanation
The correct answer is "all the above" because when determining the reactions at the supports of a structure, all three conditions must be satisfied. The algebraic sum of horizontal forces must be zero to ensure equilibrium in the horizontal direction. The algebraic sum of vertical forces must be zero to ensure equilibrium in the vertical direction. And the moment about any point must be zero to ensure rotational equilibrium. Therefore, all three conditions need to be met simultaneously to determine the reactions at the supports.
31.
D' Alembert's principle is used for
Correct Answer
A. Reducing the problem of kinetics to equivalent statics problem
Explanation
D'Alembert's principle is used to reduce the problem of kinetics to an equivalent statics problem. This principle states that the sum of the applied forces and the inertial forces acting on a body is equal to zero. By applying this principle, the dynamic problem of analyzing the motion of a system can be transformed into a static problem, making it easier to solve. This allows engineers and scientists to analyze the forces and motion of a system without considering the complexities of dynamics, simplifying the analysis process.
32.
Two coplanar couples having equal and opposite moments
Correct Answer
D. Can not balance each other
Explanation
When two coplanar couples have equal and opposite moments, it means that the moments generated by each couple cancel each other out. This implies that the net moment acting on the system is zero, resulting in a balanced system. Therefore, the two coplanar couples can balance each other.
33.
Effect of a force on a body depends upon
Correct Answer
D. All of the above
Explanation
The effect of a force on a body depends on its magnitude, direction, and position or line of action. The magnitude of a force determines its strength and how much it can change the motion or shape of an object. The direction of a force determines the way in which it will act on the object, whether it is pushing, pulling, or causing a rotation. The position or line of action of a force determines where it is applied on the object, which can affect the resulting motion or deformation. Therefore, all of these factors play a role in determining the effect of a force on a body.
34.
Forces are called concurrent when their lines of action meet in
Correct Answer
A. One point
Explanation
Forces are called concurrent when their lines of action meet at one point. This means that the forces are applied at different locations but their lines of action intersect at a single point. In other words, the forces are acting towards or away from a common point, resulting in a concurrent force system. This is different from forces that meet at two points, different planes, or perpendicular planes, as in those cases the lines of action do not intersect at a single point.
35.
The algebraic sum of the resolved parts of a number of forces in a given direction is equal to the resolved part of their resultant in the same direction. This is as per the principle of
Correct Answer
D. Resolution of forces
Explanation
The principle of resolution of forces states that the algebraic sum of the resolved parts of a number of forces in a given direction is equal to the resolved part of their resultant in the same direction. This means that when forces are resolved into their components, the sum of these components in a particular direction will be equal to the component of the resultant force in that same direction. This principle is used to analyze and solve problems involving forces acting in different directions.
36.
Which of the following is not the unit of pressure ?
Correct Answer
A. Newton
Explanation
The unit of pressure is typically measured in pascals (Pa) or its derived units such as atmospheres, millimeters of mercury, or pounds per square inch. Newton is a unit of force, not pressure. Pressure is defined as force per unit area, so newton cannot be a unit of pressure.
37.
Which of the following is not the unit of distance ?
Correct Answer
D. Milestone
Explanation
The term "milestone" does not represent a unit of distance. It is commonly used to denote a significant event or achievement. On the other hand, the other options listed (light year, angstrom, micron, and millimetre) are all units of distance measurement used in different contexts.
38.
Forces are called coplanar when all of them acting on body lie in
Correct Answer
B. One plane
Explanation
Coplanar forces are forces that lie in the same plane. This means that the forces act in the same two-dimensional space, with no forces acting in a direction perpendicular to the plane. Therefore, the correct answer is "one plane."
39.
The weight of a body is due to
Correct Answer
E. Gravitational force of attraction towards the center of the earth
Explanation
The weight of a body is due to the gravitational force of attraction towards the center of the earth. Gravitational force is the force of attraction between two objects with mass, and it is responsible for the weight of an object on the surface of the earth. The force of gravity pulls objects towards the center of the earth, giving them weight.
40.
A framed structure is perfect if it contains members equal to
Correct Answer
D. N = 2j - 3
Explanation
A framed structure is considered perfect if it contains members equal to n = 2j - 3. This equation suggests that the number of members in the structure should be two times the number of joints minus three. This is because each joint in the structure requires two members to connect to other joints, and the three is subtracted to account for the fact that the structure needs at least three members to be stable. Therefore, n = 2j - 3 ensures that the framed structure is balanced and secure.
41.
The center of gravity of a uniform lamina lies at
Correct Answer
B. The mid point of its axis
Explanation
The center of gravity of a uniform lamina lies at the midpoint of its axis because a uniform lamina has equal mass distribution throughout its body. Therefore, the center of gravity will be located at the point where the mass is evenly balanced on both sides of the axis, which is the midpoint.
42.
The possible loading in various members of framed structures are
Correct Answer
E. Compression or Tensile
Explanation
The correct answer is "Compression or Tensile". This means that the possible loading in various members of framed structures can be either compression or tension. Compression refers to the force that pushes or squeezes a member, while tension refers to the force that stretches or pulls a member. In framed structures, different members can experience either compressive or tensile forces depending on the specific loadings and structural design.
43.
The co-efficient of friction depends upon
Correct Answer
A. Nature of surfaces
Explanation
The coefficient of friction is a measure of the amount of friction between two surfaces. It depends on the nature of the surfaces, as different materials have different levels of friction. The area of contact also affects the coefficient of friction, as a larger contact area allows for more friction to be generated. Additionally, the shape of the surfaces can also impact the coefficient of friction, as irregular or rough surfaces tend to have higher friction. Therefore, all of the given options - nature of surfaces, area of contact, and shape of surfaces - affect the coefficient of friction.
44.
A cable with a uniformly distributed load per horizontal meter run will take the following shape
Correct Answer
B. Parabola
Explanation
When a cable has a uniformly distributed load per horizontal meter run, it experiences a combination of tension and compression forces. These forces cause the cable to sag in the middle and rise at the ends, resulting in a shape that resembles a parabola. This is because the parabolic shape allows for a balance between the forces acting on the cable, providing stability and minimizing deformation. Therefore, the correct answer is parabola.
45.
If a number of forces act simultaneously on a particle, it is possible
Correct Answer
B. To replace them by a single force
Explanation
When multiple forces act on a particle, it is possible to replace them by a single force. This is because the effects of all the individual forces can be combined into a single force that has the same net effect on the particle. This single force is known as the resultant force and represents the combined effect of all the individual forces. By replacing the multiple forces with a single force, it simplifies the analysis and calculations involved in studying the motion and equilibrium of the particle.
46.
Two non-collinear parallel equal forces acting in opposite direction
Correct Answer
C. Constitute a couple
Explanation
When two non-collinear parallel equal forces act in opposite directions, they create a couple. A couple consists of two equal and opposite forces that have the same line of action but different points of application. The forces in a couple do not balance each other out, but instead create a turning effect or moment. This moment is produced by the force couple's tendency to rotate an object around a point or axis. Therefore, the correct answer is "constitute a couple."
47.
According to law of triangle of forces
Correct Answer
C. If three forces acting upon a patticle are represented in magnitude and direction by the sides of a triangle, taken in order, they will be in equilibrium
Explanation
The answer states that if three forces acting upon a particle are represented in magnitude and direction by the sides of a triangle, taken in order, they will be in equilibrium. This means that if we draw a triangle where each side represents a force and the forces are arranged in order, the system will be in equilibrium. This is in accordance with the law of triangle of forces, which states that three forces acting at a point will be in equilibrium if they can be represented by a triangle.
48.
A number of forces acting at a point will be in equilibrium if
Correct Answer
C. Sum of resolved parts in any two per-pendicular directions are both zero
Explanation
The explanation for the given correct answer is that when multiple forces are acting at a point, they will be in equilibrium if the sum of the resolved parts in any two perpendicular directions is zero. This means that the forces can be broken down into their components along two perpendicular axes, and the sum of these components in each direction should add up to zero. This condition ensures that the forces are balanced and cancel each other out, resulting in a state of equilibrium.
49.
A framed structure is redundant if it contains members equal to
Correct Answer
C. N = 2j > 3
Explanation
A framed structure is redundant if it contains members equal to n = 2j > 3. This means that the number of members in the framed structure must be greater than 3 times the number of joints in the structure. If the number of members is equal to or less than 3 times the number of joints, then the structure is not redundant.
50.
The algebraic sum of moments of the forces forming couple about any point in their plane is
Correct Answer
A. Equal to the moment of the couple
Explanation
The algebraic sum of moments of the forces forming a couple about any point in their plane is equal to the moment of the couple. This means that if we take the sum of the individual moments of the forces and their distances from a reference point, it will be equal to the moment of the couple. This relationship holds true regardless of the point chosen for calculation.