Statics - Mechanics for Engineers UPDATED
ACTUAL QUESTIONS AND CORRECT
ANSWERS
The branches of Mechanics - Correct answers✔✔Mechanics is divided into statics, kinematics,
and dynamics.
The Subject of Statics - Correct answers✔✔The branch of mechanics which studies the laws of
composition of forces and the conditions of equilibrium of material bodies under the action of
forces.
Constraint body - Correct answers✔✔A body whose displacement in space is restricted by other
bodies, either connected to or in contact with it.
Smooth. Plane (Surface) or Support. - Correct answers✔✔A smooth surface is one whose
friction can be neglected in the first approximation. Therefore, the reaction N of a smooth surface
or support is directed normal to both contacting surfaces at their point of contact and is applied at
that point.
Direction of tension force - Correct answers✔✔The reaction T of the string is thus directed along
the string towards the point of suspension
Cylindrical Pin (Bearing) - Correct answers✔✔When two bodies are joined by means of a pin
passing through holes in them the connection is called a joint or hinge. In this case neither the
magnitude R nor the direction (angle a) of force R are immediately apparent.
Ba1l-and-Socket Joint and Step Bearing - Correct answers✔✔This type of constraint prevents
displacement in any direction.
, The reaction R of a ball-and-socket joint or a pivot can have any direction in space. Neither its
magnitude R nor Its angles with the x, y, and z axes are immediately apparent.
Axiom of Constraints - Correct answers✔✔Any constrained body can be treated as a free body
detached from its constraints, provided the latter are represented by their reactions.
Moment of a force about a point - Correct answers✔✔The moment of a force F about a centre O
is defined as the product of the
force magnitude and the length of the moment arm taken with appropriate sign.
The moment of a force about a centre O is
characterized by the following three elements: - Correct answers✔✔1) magnitude of the
moment, which is equal to the product of the force and the moment arm.
2) the plane of rotation through the line of action of the force F and the centre O
3) the sense of the rotation in that plane.
Formula of a moment of a force about a point. - Correct answers✔✔M = rxF
Moment of a Force with Respect to an Axis - Correct answers✔✔The moment of a force about
an axis
is a scalar quantity equal to the
moment of the projection of that
force on a plane normal to the axis with
respect to the point of intersection
of the axis and the plane.
mz(F) = mo(Fxy)= +Fxy.
ACTUAL QUESTIONS AND CORRECT
ANSWERS
The branches of Mechanics - Correct answers✔✔Mechanics is divided into statics, kinematics,
and dynamics.
The Subject of Statics - Correct answers✔✔The branch of mechanics which studies the laws of
composition of forces and the conditions of equilibrium of material bodies under the action of
forces.
Constraint body - Correct answers✔✔A body whose displacement in space is restricted by other
bodies, either connected to or in contact with it.
Smooth. Plane (Surface) or Support. - Correct answers✔✔A smooth surface is one whose
friction can be neglected in the first approximation. Therefore, the reaction N of a smooth surface
or support is directed normal to both contacting surfaces at their point of contact and is applied at
that point.
Direction of tension force - Correct answers✔✔The reaction T of the string is thus directed along
the string towards the point of suspension
Cylindrical Pin (Bearing) - Correct answers✔✔When two bodies are joined by means of a pin
passing through holes in them the connection is called a joint or hinge. In this case neither the
magnitude R nor the direction (angle a) of force R are immediately apparent.
Ba1l-and-Socket Joint and Step Bearing - Correct answers✔✔This type of constraint prevents
displacement in any direction.
, The reaction R of a ball-and-socket joint or a pivot can have any direction in space. Neither its
magnitude R nor Its angles with the x, y, and z axes are immediately apparent.
Axiom of Constraints - Correct answers✔✔Any constrained body can be treated as a free body
detached from its constraints, provided the latter are represented by their reactions.
Moment of a force about a point - Correct answers✔✔The moment of a force F about a centre O
is defined as the product of the
force magnitude and the length of the moment arm taken with appropriate sign.
The moment of a force about a centre O is
characterized by the following three elements: - Correct answers✔✔1) magnitude of the
moment, which is equal to the product of the force and the moment arm.
2) the plane of rotation through the line of action of the force F and the centre O
3) the sense of the rotation in that plane.
Formula of a moment of a force about a point. - Correct answers✔✔M = rxF
Moment of a Force with Respect to an Axis - Correct answers✔✔The moment of a force about
an axis
is a scalar quantity equal to the
moment of the projection of that
force on a plane normal to the axis with
respect to the point of intersection
of the axis and the plane.
mz(F) = mo(Fxy)= +Fxy.
