Mechanics

Question 1

Branch of mechanics that deals with forces and their effects on bodies at rest

Answer 1

Statics

Question 2

Branch of mechanics that deals with forces and their effects on bodies in motion

Answer 2

Dynamics

Question 3

Branch of dynamics that deals with bodies in motion due to the application of forces

Answer 3

Kinetics

Question 4

Branch of dynamics that deals with bodies in motion without taking into account the forces that cause such motion

Answer 4

Kinematics

Question 5

An agent which produces or tends to produce, destroy, or tends to destroy the motions of a body

Answer 5

Force

Question 6

A force acting on a body may…

Answer 6

Change the motion of a body, retard the motion of a body, balance the forces already acting on a body, and give rise to the internal stresses in a body

Question 7

To determine the effects of a force acting on a body, we must know the following characteristics of a force:

Answer 7

Magnitude of the force, line of action of the force, nature of the force (push and pull), and the point at which the force is acting

Question 8

Magnitude of force is expressed in which units…

Answer 8

Newtons in SI units, kilogram force (kgf) in MKS units

Question 9

Single force which produces the same effect as produced by all the forces acting on a body

Answer 9

Resultant force

Question 10

If two forces, acting simultaneously on a particle, are represented in magnitude and direction as two adjacent sides of a (BLANK), then their resultant may be represented in magnitude and direction by the diagonal of that (BLANK). Which law does this refer to?

Answer 10

Parallelogram law of forces

Question 11

If the resultant of a number of forces is zero, then the particle will be in…

Answer 11

Equilibrium

Question 12

When two of more forces act on a body, they are said to form a…

Answer 12

System of forces

Question 13

Forces whose lines of action lie on the same plane

Answer 13

Coplanar forces

Question 14

Forces which meet at one point

Answer 14

Concurrent forces

Question 15

Forces that meet at one point and their lines of action also lie on the same plane

Answer 15

Coplanar concurrent forces

Question 16

If three forces acting on a body are in equilibrium, then each forces is proportional to (WHAT) between the two other forces

Answer 16

The sine of the angle

Question 17

Turning effect produced by a force, on the body, on which it acts

Answer 17

Moment

Question 18

What is equal to the product of the force and perpendicular distance to the body on which it acts?

Answer 18

Moment

Question 19

SI unit of the moment of a force

Answer 19

Newton*meter

Question 20

If a number of coplanar forces acting on a particle are in equilibrium, then the algebraic sum of their (BLANK) about any point is equal to the (BLANK) of their resultant force about the same point

Answer 20

Moment

Question 21

Forces whose lines of action are parallel to each other

Answer 21

Parallel forces

Question 22

Parallel forces that act in the same direction

Answer 22

Like parallel forces

Question 23

Parallel forces that act in the opposite direction from one another

Answer 23

Unlike parallel forces

Question 24

Two equal and opposite forces whose lines of action are different (at a normal distance from one another)

Answer 24

Couple

Question 25

Perpendicular distance (x) between the lines of action of two equal and opposite forces

Answer 25

Arm of a couple

Question 26

Magnitude of a couple

Answer 26

Product of one of the forces and the arm of the couple

Question 27

A (BLANK) produces rotational motion for the body on which it acts

Answer 27

Couple

Question 28

The point through which the whole mass of the body acts, irrespective of the position of the body

Answer 28

Center of gravity

Question 29

COG of a uniform rod

Answer 29

Middle point

Question 30

COG of a rectangle

Answer 30

Point at which its diagonals intersect

Question 31

Moment of the moment, i.e. the second moment of mass or area of a body. Usually denoted with I.

Answer 31

Moment of inertia

Question 32

Distance from a given reference where the whole mass or area of the body is assumed to be concentrated to give the same value of I

Answer 32

Radius of gyration (k)

Question 33

Units for mass moment

Answer 33

kg-m2

Question 34

Units for moment of inertia

Answer 34

m4 or mm4

Question 35

If the moment of inertia about an axis passing through its center is known, then the moment of inertia about any other parallel axis is given by...

Answer 35

Parallel axis theorem

Question 36

A force acting in the opposite direction to the motion of a body

Answer 36

Friction

Question 37

Friction experienced by a body when at rest

Answer 37

Static friction

Question 38

Friction experienced by a body in motion

Answer 38

Dynamic friction

Question 39

Maximum value of frictional force that comes into play when a body just begins to slide over the surface of the other body

Answer 39

Limiting friction

Question 40

Laws of static friction...

Answer 40

Opposite direction to body, magnitude is equal to the force that tends to move the body, magnitude of limiting friction bears a constant ratio to the normal reaction, force is independent to the area of contact, force depends on the roughness

Question 41

Laws of dynamic friction

Answer 41

Opposite direction, magnitude bears a constant ratio to the normal reaction, slight decrease with increase in speed

Question 42

Ratio of limiting friction (F) to the normal reaction (Rn) between the two bodies

Answer 42

Coefficient of friction (mu)

Question 43

Device that enables us to lift a heavy load, W, by a comparatively small effort, P

Answer 43

Lifting machine

Question 44

Ratio of load lifted (W) to the effort applied (P)

Answer 44

Mechanical advantage

Question 45

Ratio of the distance moved by the effort to the distance moved by the load

Answer 45

Velocity ratio

Question 46

Work done on the machine, equal to the product of effort and the distance through which it moves

Answer 46

Input of the machine

Question 47

Work done by the machine, equal to the product of load lifted and distance through which it has been lifted

Answer 47

Output of the machine

Question 48

Ratio of output to input of the machine

Answer 48

Efficiency of the machine

Question 49

Structure, made up of several bars, riveted or welded together

Answer 49

Truss or frame

Question 50

Composed of members just sufficient to keep it in equilibrium, when loaded, without any change in its shape. "n = 2j-3"

Answer 50

Perfect frame

Question 51

Rate of change of displacement with respect to its surrounding. Scalar quantity

Answer 51

Speed

Question 52

Rate of change of displacement with respect to its surrounding, in a particular direction. Vector quantity.

Answer 52

Velocity

Question 53

Rate of change of velocity in a body. Positive when velocity increases with time, negative when velocity decreases with time.

Answer 53

Acceleration

Question 54

In the case of vertical motion, acceleration (a) can be substituted for...

Answer 54

g = 9.81 m/s2

Question 55

When a body falls from a height, its velocity is equal to...

Answer 55

v = sqrt(2gh)

Question 56

Every body continues in a state of rest or uniform motion unless acted upon, the rate of change of momentum is directly proportional to the impressed force and takes place in the same direction in which the force acts, and for every action there is an equal and opposite reaction

Answer 56

Newton's Laws of Motion

Question 57

Matter contained in a body

Answer 57

Mass

Question 58

Force by which a body is attracted towards the center of the earth

Answer 58

Weight

Question 59

Total motion possessed by a body

Answer 59

Momentum (mass x velocity)

Question 60

Force equal in magnitude but opposite and collinear with the applied force producing the acceleration

Answer 60

Inertia force

Question 61

The force, while acting upon a body of mass 1 kg, that produces an acceleration of 1 m/s2 in the direction of which it acts

Answer 61

Newton = 1 kg*m/s2

Question 62

The path traced by a projectile in space

Answer 62

Trajectory

Question 63

Total time taken by a projectile to reach maximum height and return to the ground

Answer 63

Time of flight

Question 64

Distance between the point of projection and the point where the projectile strikes the ground

Answer 64

Range

Question 65

Angle described by a particle from one point to another, with respect to time. Vector quantity.

Answer 65

Angular displacement

Question 66

Rate of change of angular displacement of a body. Usually expressed in revolutions per minute (rpm) or radians per second (rad/s). Denoted by omega.

Answer 66

Angular velocity

Question 67

Angular velocity equation:

Answer 67

omega = (2*pi*N)/60 rad/s, given N [rpm]

Question 68

Rate of change of angular velocity

Answer 68

Angular acceleration

Question 69

The normal component of linear acceleration along a circular path

Answer 69

Centripetal acceleration

Question 70

When the body moves along a circular path with uniform velocity, then it will only have...

Answer 70

Centripetal acceleration

Question 71

When a body moves along a straight path, then it will have only...

Answer 71

Tangential acceleration

Question 72

A body is said to vibrate with simple harmonic oscillation, if it satisfies two conditions:

Answer 72

Acceleration directed towards center, acceleration proportional to distance from center

Question 73

Maximum displacement of a body from its mean position

Answer 73

Amplitude

Question 74

Time taken for one complete revolution of a particle in harmonic oscillation

Answer 74

Periodic time

Question 75

Number of cycles per second and reciprocal of time period

Answer 75

Frequency

Question 76

Heavy bob suspended at the end of a light inextensible and flexible string

Answer 76

Simple pendulum

Question 77

Bodies which rebound after impact are called...

Answer 77

Elastic bodies

Question 78

Bodies which do not rebound after impact are called...

Answer 78

Inelastic bodies

Question 79

Whenever a force acts on a body and the body undergoes a displacement in the direction of force, then (BLANK) is said to be done

Answer 79

Work

Question 80

Mathematically, work done is defined as...

Answer 80

Work done = force * displacement

Question 81

The unit for work done

Answer 81

N*m

Question 82

Rate of doing work per unit time

Answer 82

Mechanical power

Question 83

Unit for mechanical power

Answer 83

Watt (N*m/s)

Question 84

Product of force on an object and the object's velocity

Answer 84

Power

Question 85

Capacity for doing work. Mathematically, equal to the work done on a body in altering either its position or its velocity.

Answer 85

Mechanical energy

Question 86

Energy possessed by a body for doing work, by virtue of its position

Answer 86

Potential energy

Question 87

Potential energy stored by an elastic body when deformed

Answer 87

Strain energy

Question 88

Energy possessed by a body, for doing work

Answer 88

Kinetic energy