What is the formula for calculating the efficiency of a machine?
A (Output force / Input force) × 100
B (Input work / Output work) × 100
C (Output work / Input work) × 100
D (Input force / Output force) × 100
Efficiency is the ratio of output work to input work, expressed as a percentage. It measures how effectively a machine converts input energy into useful output work.
Which of the following is true for a cantilever beam?
A It is used only for vertical loads
B It allows rotation at both ends
C It has supports at both ends
D It is fixed at one end and free at the other
A cantilever beam is fixed at one end and free at the other. It is commonly used in structures like balconies and bridges, where one end is anchored.
What is the formula for calculating the angular acceleration?
A Change in angular velocity / Time
B Force × Distance
C Mass × Acceleration
D Force / Area
Angular acceleration (α) is the rate of change of angular velocity with respect to time. It is calculated as α = Δω / t, where Δω is the change in angular velocity.
Which of the following is true for a truss structure?
A It carries bending moments
B It cannot carry tension
C It carries only axial loads
D It is made of curved members
A truss structure consists of straight members connected at joints, and it carries only axial loads (tension or compression). It is designed to be lightweight and efficient.
What is the formula for calculating the coefficient of friction?
A Frictional force / Normal force
B Normal force / Frictional force
C Mass × Acceleration
D Force × Distance
The coefficient of friction (μ) is the ratio of the frictional force to the normal force. It is a dimensionless quantity that depends on the nature of the surfaces in contact.
Which of the following is true for a free-body diagram?
A It includes internal forces
B It shows only external forces
C It ignores equilibrium
D It is used only for beams
A free-body diagram (FBD) is a graphical representation of all external forces acting on a body. It is used to analyze forces and moments in equilibrium problems.
What is the formula for calculating the center of mass?
A Sum of forces / Total mass
B Sum of moments / Total mass
C Sum of distances / Total volume
D Sum of areas / Total length
The center of mass (COM) is calculated as the sum of the moments of individual masses divided by the total mass. It is the point where the mass is balanced.
Which of the following is true for a rigid body?
A It is only used in fluid mechanics
B It cannot rotate
C It deforms under load
D It has no deformation under load
A rigid body is an idealized object that does not deform under load. It is used in mechanics to simplify the analysis of motion and equilibrium.
What is the formula for calculating the angular momentum?
A Force × Distance
B Mass × Acceleration
C Force / Area
D Mass × Velocity × Radius
Angular momentum (L) is the rotational equivalent of linear momentum. It is calculated as L = m × v × r, where m is mass, v is velocity, and r is the radius of rotation.
Which of the following is true for a simply supported beam?
A It has fixed supports at both ends
B It is used only for vertical loads
C It has a hinge support at one end and a roller at the other
D It cannot carry bending moments
A simply supported beam has a hinge support at one end and a roller support at the other. It allows rotation and horizontal movement at the supports.
What is the formula for calculating the strain energy?
A 1/2 × Stress × Strain × Volume
B Force × Distance
C Mass × Acceleration
D Force / Area
Strain energy is the energy stored in a material due to deformation. It is calculated as U = 1/2 × σ × ε × V, where σ is stress, ε is strain, and V is volume.
Which of the following is true for a pulley system?
A It changes the direction of force
B It has no mechanical advantage
C It decreases the input force
D It increases the input force
A pulley system is used to change the direction of the applied force. It can also provide mechanical advantage depending on the number of pulleys used.
What is the formula for calculating the mechanical advantage of a lever?
A Load arm / Effort arm
B Force × Distance
C Effort arm / Load arm
D Mass × Acceleration
The mechanical advantage (MA) of a lever is the ratio of the effort arm to the load arm. It indicates how much the lever amplifies the input force.
Which of the following is true for a centroid?
A It is the geometric center of an area
B It is the balance point of a body
C It is the same as the center of gravity
D All of the above
The centroid is the geometric center of an area, the balance point of a body, and is often the same as the center of gravity for uniform density objects.
What is the formula for calculating the work-energy principle?
A Work done = Change in potential energy
B Work done = Change in kinetic energy
C Work done = Force × Distance
D Work done = Mass × Acceleration
The work-energy principle states that the work done on an object is equal to the change in its kinetic energy. It is expressed as W = ΔKE.