The unit of force in the International System (SI) is Newton (N). One Newton is defined as the force required to accelerate a 1 kg mass by 1 meter per second squared.
Which of the following is a scalar quantity?
A Mass
B Acceleration
C Force
D Velocity
Mass is a scalar quantity because it has only magnitude and no direction, unlike force, velocity, and acceleration, which are vector quantities.
What does equilibrium mean in engineering mechanics?
A Forces exceed each other
B Forces balance each other
C No motion
D Objects remain in motion
Equilibrium means that the net force acting on a body is zero, and the body remains either at rest or moves at constant velocity.
What is the main principle behind hydrostatics?
A Pressure decreases with depth
B Pressure is constant at all depths
C Pressure is inversely proportional to volume
D Pressure increases with depth
In hydrostatics, the pressure in a fluid increases with depth due to the weight of the fluid above. This relationship is given by P = ρgh, where ρ is density, g is acceleration due to gravity, and h is depth.
Which of the following is used to measure the amount of deformation in a material?
A Force
B Strain
C Acceleration
D Stress
Strain is the measure of deformation representing the displacement between particles in a material. It is dimensionless and calculated as the change in length divided by the original length.
What is the purpose of a free-body diagram in mechanics?
A To show forces acting on a system
B To determine speed
C To calculate acceleration
D To find the mass of the object
A free-body diagram is used to show all the external forces acting on a body, which helps in analyzing its motion and equilibrium.
Which of the following is true about a truss structure?
A It carries bending moments
B It carries torsional forces
C It carries only axial loads
D It is made of curved members
A truss is a structure made up of straight members and joints. It only carries axial loads, either tension or compression, and is not designed for bending moments or torsional forces.
What is the formula for work done by a force?
A Work = Force × Distance
B Work = Force × Time
C Work = Force × Velocity
D Work = Mass × Acceleration
Work done is the product of the force applied and the distance moved in the direction of the force. It is measured in Joules.
Which of the following defines the concept of mechanical advantage?
A The ratio of velocity to distance
B The force required to move an object
C The ratio of output force to input force
D The work done by a machine
Mechanical advantage is the ratio of the force that is amplified by a machine to the force you apply. It indicates how much a machine multiplies the input force.
What is the centroid of an object?
A The center of mass
B The geometric center
C The center of gravity
D The point where all forces act
The centroid is the center of the shape’s area or volume. It is the point that can be considered as the center of a uniform object’s mass distribution.
What does the moment of a force depend on?
A The magnitude of the force
B The distance from the pivot
C The direction of the force
D Both the magnitude of the force and the distance
The moment (torque) of a force depends on both its magnitude and the perpendicular distance from the pivot point to the line of action of the force.
Which type of motion analysis focuses on forces and moments?
A Kinematics
B Rigid body mechanics
C Fluid dynamics
D Particle dynamics
Rigid body mechanics studies the motion of objects without deformation under load. It includes analyzing forces, moments, and their effect on rigid bodies.
Which principle is used to find the unknown forces in a structure?
A Virtual work principle
B Strain-energy principle
C Work-energy principle
D Hydrostatic principle
The principle of virtual work is used to calculate forces in structures by considering virtual displacements. It helps in finding equilibrium conditions in mechanical systems.
What does the term “impulse” refer to in mechanics?
A Distance over time
B Force over time
C Momentum change
D Speed multiplied by time
Impulse refers to the change in momentum of an object when a force is applied over a period of time. It is equal to the force multiplied by the time duration of the force.
What is the purpose of stability analysis in engineering?
A To measure forces in the structure
B To predict failure of structures
C To calculate bending moments
D To ensure a structure does not collapse
Stability analysis ensures that a structure remains stable under applied loads and does not collapse or undergo undesirable deformation, ensuring its safety and reliability.