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Mechanical Engineering :: Engineering Mechanics

  1. Three forces acting on a rigid body are represented in magnitude, direction and line of action by the three sides of a triangle taken in order. The forces are equivalent to a couple whose moment is equal to

  2. A.

    area of the triangle

    B.

    twice the area of the triangle

    C.

    half the area of the triangle

    D.

    none of these


  3. If tension in the cable supporting a lift moving downwards is half the tension when it is moving upwards, the acceleration of the lift is

  4. A.

    g/2

    B.

    g/3

    C.

    g/4

    D.

    none of these


  5. Efficiency of a screw jack is given by(where α = Helix angle, and φ = Angle of friction.)

  6. A.

    \(\frac { tan(\alpha + \phi) } {tan\alpha }\)

    B.

    \(\frac {tan\alpha } { tan(\alpha + \phi) }\)

    C.

    \(\frac { tan(\alpha - \phi) } {tan\alpha } \)

    D.

    \(\frac {tan\alpha } { tan(\alpha - \phi) } \)


  7. When a train is rounding a curve, the side thrust on the wheel flanges is prevented by raising the outer edge of the rail.

  8. A.

    Yes

    B.

    No


  9. Frequency of vibrations means the number of cycles per second.

  10. A.

    Yes

    B.

    No