Mechanics & Strength of Materials 3

Objective Questions and Answer: Mechanics & Strength of Materials 3

Subject:  Mechanics & Strength of Materials 3

Part 3: Objective questions and answers of Mechanics & Strength of Materials

Q1. A body will begin to move down an inclined plane if the angle of inclination of the plane is ______ the angle of friction

a) Equal to

b) Less than

c) Greater than

d) None of the above

Q2. Coefficient of friction depends upon

a) Area of contact only

b) Nature of surface only

c) Both (a) and (b)

d) None of these

Q3. The force required to move the body up the plane will be minimum if it makes an angle with the inclined plane ______ the angle of friction.

a) Equal to

b) Less than

c) Greater than

d) None of the above

Q4. A ladder is resting on a smooth ground and leaning against a rough vertical wall. The force of friction will act

a) Towards the wall at its upper end

b) Away from the wall at its upper end

c) Downward at its upper end

d) Upward at its upper end

Q5. A ladder is resting on a rough ground and leaning against a smooth vertical wall. The force of friction will act

a) Downward at its upper end

b) Upward at its upper end

c) Zero at its upper end

d) Perpendicular to the wall at its upper end

Q6. In a screw jack, the effort required to lower the load is ______ the effort required to raise the same load.

a) Less than

b) Equal to

c) More than

d) None of the above

Q7. An ideal machine is one whose efficiency is

a) Between 60 and 70 percent

b) Between 70 and 80 percent

c) Between 80 and 90 percent

d) 100 percent

Q8. The mechanical advantage of a lifting machine is the ratio of

a) Distance moved by effort to the distance moved by load

b) Load lifted to the effort applied

c) Output to the input

d) All of the above

Q9. The efficiency of a lifting machine is the ratio of

a) Output to the input

b) Work done by the machine to the work done on the machine

c) Mechanical advantage to the velocity ratio

d) All of the above

Q10. In ideal machine, mechanical advantage is ______velocity ratio.

a) Equal to

b) Less than

c) Greater than

d) None of the above

Q11. In actual machines, mechanical advantage is ______velocity ratio.

a) Equal to

b) Less than

c) Greater than

d) None of the above

Q12. A machine having an efficiency less than 50 percent, is known as

a) Reversible machine

b) Non-reversible machine

c) Neither reversible nor non-reversible machine

d) Ideal machine

Q13. A machine having an efficiency greater than 50 percent, is known as

a) Reversible machine

b) Non-reversible machine

c) Neither reversible nor non-reversible machine

d) Ideal machine

Q14. A screw jack used for lifting the load is

a) A reversible machine

b) A non-reversible machine

c) An ideal machine

d) None of these

Q15. For a self locking machine, the efficiency must be

a) Equal to 50 percent

b) Less than 50 percent

c) Greater than 50 percent

d) 100 percent

Q16. Which of the following statement is wrong?

a) A force acting in the opposite direction to the motion of the body is called force of friction.

b) The ratio of the limiting friction to the normal reaction is called coefficient of friction.

c) A machine whose efficiency is 100 percent is known as an ideal machine.

d) The velocity ratio of a machine is the ratio of load lifted to the effort applied.

Q17. If the number of pulleys in a system is equal to its velocity ratio, then it is a

______system of pulleys

a) First

b) Second

c) Third

d) None of these

Q18. The velocity ratio of a single purchase crab winch can be increased by

a) Increasing the length of the handle

c) Increasing the number of teeth of the pinion

d) All of the above

Q19. A framed structure is perfect, if the number of members are ______ (2j-3), where j is the number of joints.

a) Equal to

b) Less than

c) Greater than

d) Either (b) or (c)

Q20. A framed structure is imperfect, if the number of members are ______ (2j-3).

a) Equal to

b) Less than

c) Greater than

d) Either (b) or (c)

Part 3: Objective questions and answers of Mechanics & Strength of Materials