On a ladder resting on smooth ground and leaning against vertical wall, the force of friction will be__________________?

Related Mcqs:

1. On the ladder resting on the ground and leaning against a smooth vertical wall, the force of friction will be__________________?

   A. downwards at its upper end
   B. upwards at its upper end
   C. perpendicular to the wall at its upper end
   D. zero at its upper end
   E. none of the above

2. 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 sur-faces
   E. will be in equilibrium under all condi-tions

3. Pick up wrong statement about friction force for dry surfaces. Friction force is________________?

   A. proportional to normal load between the surfaces
   B. dependent on the materials of contact surface
   C. proportional to velocity of sliding
   D. independent of the area of contact surfaces
   E. none of the above is wrong statement

4. A semi-circular disc rests on a horizontal surface with its top flat surface horizontal and circular portion touching down. The coefficient of friction between semi-cricular disc and horizontal surface is i. This disc is to be pulled by a horizontal force applied at one edge and it always remains horizontal. When the disc is about to start moving, its top horizontal force will____________________?

   A. remain horizontal
   B. slant up towards direction of pull
   C. slant down towards direction of pull
   D. unpredictable
   E. none of the above

5. Dynamic friction as compared to static friction is________________?

   A. same
   B. more
   C. less
   D. may be less of more depending on nature of surfaces and velocity
   E. has no correlation

6. Coulomb friction is the friction between_________________?

   A. bodies having relative motion
   B. two dry surfaces
   C. two lubricated surfaces
   D. solids and liquids
   E. electrically charged particles

7. The resultant of the following three couples 20 kg force, 0.5 m arm, $ ve sense 30 kg force, 1 m arm, – ve sense 40 kg force, 0.25 m arm, + ve sense having arm of 0.5 m will be_________________?

   A. 20 kg, – ve sense
   B. 20 kg, + ve sense
   C. 10 kg, + ve sense
   D. 10 kg, – ve sense
   E. 45 kg, + ve sense

8. Least force required to draw a body up the inclined plane is W sin (plane inclination + friction angle) applied in the direction__________________?

   A. along the plane
   B. horizontally
   C. vertically
   D. at an angle equal to the angle of friction to the inclined plane
   E. unpredictable

9. The centre of percussion of a solid cylinder of radius r resting on a horizontal plane will be______________?

   A. r/2
   B. 2r/3
   C. r/A
   D. 3r/2
   E. 3r/A

10. The center of percussion of the homogeneous rod of length L suspended at the top will be__________________?

    A. L/2
    B. L/3
    C. 3L/4
    D. 2L/3
    E. 3L/8