631. Which of the following is not a vector quantity
A.Weight
B.Velocity
C.Acceleration
D.Force

632. According to law of triangle of forces
A.Three forces acting at a point will be in equilibrium
B.Three forces acting at a point can be represented by a triangle, each side being proportional to force
C.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
D.If three forces acting at a point are in equilibrium, each force is proportional to the sine of the angle between the other two

633. If a rigid body is in equilibrium under the action of three forces, then
A.These forces are equal
B.The lines of action of these forces meet in a point
C.The lines of action of these forces are parallel
D.(B) and (C) above

634. If two forces each equal to P in magnitude act at right angles, their effect may be neutralised by a third force acting along their bisector in opposite direction whose magnitude is equal to
A.2P
B.P/2
C.?2P
D.P/?2

635. D’ Alembert’s principle is used for
A.Reducing the problem of kinetics to equivalent statics problem
B.Determining stresses in the truss
C.Stability of floating bodies
D.Designing safe structures

636. A heavy ladder resting on floor and against a vertical wall may not be in equilibrium, if
A.The floor is smooth, the wall is rough
B.The floor is rough, the wall is smooth
C.The floor and wall both are smooth surfaces
D.The floor and wall both are rough surfaces

637. According to Lami’s theorem
A.Three forces acting at a point will be in equilibrium
B.Three forces acting at a point can be represented by a triangle, each side being proportional to force
C.If three forces acting upon a particle are represented in magnitude and direction by the side of a triangle, taken in order, they will be in equilibrium
D.If three forces acting at a point are in equilibrium, each force is proportional to the sine of the angle between the other two

638. The product of either force of couple with the arm of the couple is called
A.Resultant couple
B.Moment of the forces
C.Resulting couple
D.Moment of the couple

639. In determining stresses in frames by methods of sections, the frame is divided into two parts by an imaginary section drawn in such a way as not to cut more than
A.Two members with unknown forces of the frame
B.Three members with unknown forces of the frame
C.Four members with unknown forces of the frame
D.Three members with known forces of the frame

640. Two coplaner couples having equal and opposite moments
A.Balance each other
B.Can not balance each other
C.Are equivalent
D.Produce a moment of couple

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