1. Mechanical advantage is the ratio of effort to load.
a) True
b) False
Explanation: Mechanical advantage is the ratio of load to effort.
2. Leverage is the ratio of load arm to effort arm.
a) True
b) False
Explanation: Leverage is the ratio of effort arm to load arm.
3. The distance between fulcrum and dead weights is 100mm. Dead weights are of 2945.2N. An effort of 294.52N acts on the other hand. Find the distance between the fulcrum and other end of the lever..
a) 1000mm
b) 100mm
c) 10mm
d) 10000mm
Explanation: F ₂xl₂ =F₁ xl₁.
4. A right angled bell-crank is designed to raise a load of 5kN at short arm whose length is 100mm. Longer arm is of length 500mm. Calculate the reaction or force acting on the fulcrum.
a) 5.1
b) 5.8
c) 6.1
d) 6.8
Explanation: Force required for raising at longer end is found by F ₂xl₂ =F₁ xl₁. Reaction at fulcrum is
√ (F₁²+F₂²) as the two forces are perpendicular.
5. A right angled bell-crank is designed to raise a load of 5kN at short arm whose length is 100mm. Also longer arm is of length 500mm. If permissible bearing pressure on pin is 10N/mm² and diameter of the 20mm, find the length of the pin.
a) 35.5mm
b) 25.5mm
c) 20mm
d) 30mm
Explanation: R=p x d x L. Here R=√ (F₁²+F₂²).
6. A right angled bell-crank is designed to raise a load of 5kN at short arm whose length is 100mm. Also longer arm is of length 500mm. If permissible bearing pressure on pin is 10N/mm² and diameter of the 20mm, find the shear stress in the pin.
a) 8.12
b) 8.51
c) 9.12
d) 9.51
Explanation: τ=R/(2 x π x d²/4) as the pin is subjected to double shear. Also R=√ (F₁²+F₂²) and F ₂xl₂ =F₁ xl₁.
7. How many classes of levers are there?
a) 2
b) 3
c) 4
d) 5
Explanation: The three classes are Fulcrum in the middle, Resistance in the middle and Effort in the middle.
8. A bottle opener belongs to which class of the levers.
a) Effort in the middle
b) Fulcrum in the middle
c) Resistance in the middle
d) None of the mentioned
Explanation: In a bottle opener fulcrum can be considered at the end and resistance in middle as the actual work is done on the bottle cap which lies in middle of opener.
9. Fulcrum can be located at one end of the lever.
a) True
b) False
Explanation: Fulcrum can be located in middle or at one end of the lever.
10. Stress concentration is defined as the localization of high stresses due to irregularities present in the component and no changes of the cross section.
a) True
b) False
Explanation: The given statement is true apart from the fact that there is no change in the cross section.