1. In a simple machine, whose velocity ratio is 30, a load of 2400 N is lifted by an effort of 150 N and a load of 3000 N is lifted by an effort of 180 N. Find the law of machine (a) P = 0.50W + 144 (b) P = 0.60W + 25 (c) P = 0.05 W + 144 (d) P = 0.05 W + 30 Ans: d 3. In a lifting machine, an effort of 500 N is to be moved by a distance of 20 m to raise a load of 10,000 N by a distance of 0.8 m. Determine the velocity ratio and mechanical advantage. (a) 10 and 35 (b) 20 and 35 (c) 10 and 25 (d) 25 and 20 Ans: d 4. In a lifting machine, an effort of 500 N is to be moved by a distance of 20 m to raise a load of 10,000 N by a distance of 0.8 m. Determine the effort lost in friction. (a) 100 N (b) 10 N (c) 278 N (d) 136 N Ans: a 5. In a simple machine, whose velocity ratio is 30, a load of 2400 N is lifted by an effort of 150 N and a load of 3000 N is lifted by an effort of 180 N. calculate the load that could be lifted by a force of 200 N. (a) 4400 N
(b) 1400 N (c) 2400 N (d) 3400 N Ans: d 6. In a simple machine, whose velocity ratio is 30, a load of 2400 N is lifted by an effort of 150 N and a load of 3000 N is lifted by an effort of 180 N. calculate the amount of effort wasted in overcoming the friction using a force of 200 N. (a) 86.67 N (b) 72.67 N (c) 96.67 N (d) 52.67 N Ans: a 7. In a lifting machine an effort of 150 N raised a load of 7700 N. What are the mechanical advantage and velocity ratio if the efficiency at this load is 60%. (a) 51.33 and 85.55 (b) 33.51 and 55.85 (c) 56.23 and 88.75 (d) 23.56 and 75.88 Ans: a 8. A load of 13,200 N is raised by an effort of 250 N, what is the efficiency? If VR is 85.55 (a) 61.72% (b) 48.27% (c) 86.67% (d) 54.33% Ans: a
9. in an ideal machine, (a) Velocity Ratio > Mechanical Advantage (b) Velocity Ratio =0.5 X Mechanical Advantage (c) Velocity Ratio < Mechanical Advantage (d) Velocity Ratio = Mechanical Advantage Ans: d 10. From the law of machine, for an ideal machine, the intercept is (a) 0 (b) less than 0 (c) always greater than 0 (d) 1 Ans: a 11. From the relations below which one is correct, for an ideal machine? (a) W/P=2.VR (b) W/P= VR (c) W/P= 0.5VR (d) VR =1.5W/P Ans: b 12. Ideal Load can be expressed by (a)
Wi =
VR × 2P
(b) Wi = VR × P (c) Wi = VR × P
2
(d) Wi = VR × 0.5P Ans: b
13. Ideal Effort can be expressed by (a)
Pi =2W/VR
(b) Pi =W/VR 2
(c) Pi =W /VR (d) Pi =0.5W/VR Ans: b 14. In an ideal machine, (a) Output of a machine > Input of a machine (b) Output of a machine =0.5 X Input of a machine (c) Output of a machine < Input of a machine (d) Output of a machine = Input of a machine Ans: d 15. In practice, why it is difficult to get an ideal machine? (a) Work done is utilised to overcome frictional resistance. (b) Useful work done in lifting the load is reduced. (c) It occurs the reduction of efficiency. (d) All these reasons are valid. Ans: d 16. The law of machine can be expressed mathematically in the form of (a) Parabola (b) Circle (c) Straight line (d) Any of these Ans: c
17. In practice, maximum mechanical advantage equals to 2
(a) 1/m
(b) 1/m X 1/VR (c) 1/m (d) 1/VR Ans: c 18. From the law of machine, C/W which is in denominator, (a) Increases and hence mechanical advantage increases. (b) Decreases and hence efficiency increases. (c) Decreases and hence mechanical advantage increases. (d) As the load increases remains same. Ans: c 19. The variation of mechanical advantage with respect to load (a) Parabola (b) Circle (c) Straight line (d) Any of these Ans: a 20. The variation of the efficiency with load (a) Parabola (b) Circle (c) Straight line (d) Any of these Ans: a
21. The velocity ratio ( VR) for a machine is (a) Always constant (b) Varies with effort (P) (c) Varies with machine input (d) Varies with machine output Ans: a 22. Which one is correct below for a simple machine? (a) Variation of efficiency with load is similar to the variation of mechanical advantage with the load. (b) Variation of efficiency with load is similar to the variation of velocity ratio with the load. (c) Variation of efficiency with load is similar to the variation of machine output with the load. (d) Variation of efficiency with load is similar to the variation of machine input with the load. Ans: a 23. Effort wasted in overcoming the friction can be given as (a) Actual effort - Ideal effort (b) Actual effort - Ideal load (c) Ideal effort - Actual effort (d) Actual load - Ideal load Ans: a 23. The efforts required for lifting various loads by a lifting machine is shown by the plot below, Determine the law of machine, if the velocity ratio is 25. P and W are in KN.
(a) P = 0.06 W + 10 (b) P = 0.60 W + 20 (c) P = 0.09 W + 10 (d) P = 0.90 W + 20 Ans: a 25. In a lifting machine, an effort of 500 N is to be moved by a distance of 20 m to raise a load of 10 KN by a distance of 0.8 m. Determine the velocity ratio, mechanical advantage and efficiency of the machine respectively. (a) 25, 20 and 80% (b) 25, 50 and 70% (c) 25, 50 and 80% (d) 25, 20 and 70% Ans: a 26. In a lifting machine, an effort of 500 N is to be moved by a distance of 20 m to raise a load of 10 KN by a distance of 0.8 m. Determine effort lost in friction. (a) 100 N (b) 100 KN (c) 400 N
(d) 400 KN Ans: a 27. In a lifting machine, an effort of 500 N is to be moved by a distance of 20 m to raise a load of 10 KN by a distance of 0.8 m. Determine frictional resistance. (a) 2500 N (b) 12500 N (c) 1250 N (d) 25000 N Ans: a 28. Frictional resistance can be given as (a) Actual effort - Ideal effort (b) Actual effort - Ideal load (c) Ideal effort - Actual effort (d) Ideal load - Actual load Ans: d 29. In a simple machine, whose velocity ratio is 30, a load of 2400 N is lifted by an effort of 150 N and a load of 3000 N is lifted by an effort of 180 N. Calculate the load that could be lifted by a force of 200 N. (a) 3400 N (b) 2400 N (c) 4400 N (d) 1400 N Ans: a 30. In a simple machine, whose velocity ratio is 30, a load of 2400 N is lifted by an effort of 150 N and a load of 3000 N is lifted by an effort of 180 N. Calculate the amount of effort wasted in overcoming the friction. (a) 86.67 N
(b) 66.67 N (c) 33.67 N (d) 56.67 N Ans: a 31. In a lifting machine an effort of 150 N raised a load of 7700 N. The efficiency at this load is 60%, by the same machine, a load of 13,200 N is raised by an effort of 250 N; calculate the maximum mechanical advantage and the maximum efficiency. (a) 55 (b) 44 (c) 66 (d) 33 Ans: a 32. In a lifting machine an effort of 150 N raised a load of 7700 N. The efficiency at this load is 60%, by the same machine, a load of 13,200 N is raised by an effort of 250 N; calculate the maximum efficiency. (a) 64.29% (b) 44.22% (c) 76.85% (d) 52.36% Ans: a 33. A simple lifting machine will be reversible or self-locking solely based on its (a) Efficiency (b) Input to the machine (c) Output to the machine (d) Distance moved by effort
Ans: a 34. The law of machine can be expressed for an ideal machine as
Ans: b 35. A lifting machine is self-locking if its efficiency is (a) Greater than 50 per cent (b) Less than 50 per cent (c) Greater than 100 per cent (d) Less than 100 per cent Ans: b 36. In a lifting machine, the condition for the reversibility is (a) Output > Frictional resistant (b) Output < Frictional resistant (c) Effort wasted in overcoming the friction < output (d) Input > Frictional resistant Ans: a
37. In a lifting machine having velocity ratio is 30; a load of 5000 N is lifted with an effort of 360 N. Determine whether it is self-locking or reversible machine. How much is the frictional resistance? (a) Self-locking machine (b) Reversible machine (c) Ideal machine (d) None of these Ans: a 38. In a lifting machine having velocity ratio is 27.778; a load of 5000 N is lifted with an effort of 360 N. Determine whether it is (a) Self-locking machine (b) Reversible machine (c) Ideal machine (d) None of these Ans: d 39. In a lifting machine having velocity ratio is 30; a load of 5000 N is lifted with an effort of 360 N. How much is the frictional resistance? (a) 5.8 KN (b) 3.2 KN (c) 8.3 KN (d) 9.4 KN Ans: a 40. From the maximum M.A. and the maximum efficiency relations which of the following is not correct? (a) M.A. increases with load, (b) Efficiency η decreases with load, (c) M.A. will be maximum at a very high value of load,
(d) Efficiency η will be maximum at a very high value of load. Ans: b 40. In a lifting machine a load of 100 N is moved through a distance of 5 cm, by an effort P moving through a distance of 80 cm. Calculate the value of P if the efficiency of the machine is 60%. (a) 10.42 N (b) 18.68 N (c) 43.26 N (d) 25.34 N Ans: a 41. A machine raised a load of 360 N through a distance of 200 mm. The effort, a force of 60 N moved 1.8 m during the process. Calculate Efficiency at this load. (a) 66.66% (b) 44.67% (c) 55.66% (d) 86.66% Ans: a 42. A machine raised a load of 360 N through a distance of 200 mm. The effort, a force of 60 N moved 1.8 m during the process. Calculate the effort lost in friction. (a) 20 N (b) 28 N (c) 10 N (d) 35 N Ans: a
43. A machine raised a load of 360 N through a distance of 200 mm. The effort, a force of 60 N moved 1.8 m during the process. Calculate the frictional resistance in terms of load. (a) 180 N (b) 850 N (c) 260 N (d) 440 N Ans: a 44. The law of a certain lifting machine is P =W/50+ 1.5. The velocity ratio of the machine is 100. Determine the effort required to overcome friction while lifting a load of 150 N. (a) 3N (b) 30 N (c) 6 N (d) 60 N Ans: a 45. The law of a certain lifting machine is P =W/50+ 1.5. The velocity ratio of the machine is 100. Find the maximum possible mechanical advantage and maximum possible efficiency of the machine. (a) 50 and 50% (b) 50 and 60% (c) 60 and 50% (d) 60 and 60% Ans: a 45. What load will be lifted by an effort of 12 N if the velocity ratio is 18 and the efficiency of the machine at this load is 60%.
(a) 130N (b) 260 N (c) 65 N (d) 390 N Ans: a 46. A load will be lifted by an effort of 12 N, the velocity ratio is 18 and the efficiency of the machine at this load is 60%, if the machine has a constant frictional resistance, determine the law of machine. (a) P = W/18 + 4.8 (b) P = W/8 + 6.4 (c) P = W/14 + 8.2 (d) P = W/10 + 7.6 Ans: a 47. In a lifting machine, the efforts required to lift loads of 20 N and 30 N were 5 N and 6 N respectively. If the velocity ratio of the machine is 20, determine the law of the machine. (a) P = W/10 + 3.0 (b) P = W/20 + 6.0 (c) P = W/10 + 4.5 (d) P = W/20 + 1.5 Ans: a 48. In a lifting machine, the efforts required lifting loads of 20 N and 30 N were 5 N and 6 N respectively. If the velocity ratio of the machine is 20, determine efficiencies corresponding to loads of 20 N and 30 N, (a) 20 %and 25% (b) 35% and 55% (c) 30% and 50%
(d) 60% and 65% Ans: a 49. In a lifting machine, the efforts required lifting loads of 20 N and 30 N were 5 N and 6 N respectively. If the velocity ratio of the machine is 20, determine effort lost in friction in both cases of 20 N and 30 N, (a) 4 N and 4.5 N (b) 4.5 N and 5 N (c) 5.5 N and 6 N (d) 6.5 N and 7 N Ans: a 50. In a lifting machine, the efforts required lifting loads of 20 N and 30 N were 5 N and 6 N respectively. If the velocity ratio of the machine is 20, determine Maximum possible efficiency of the machine, (a) 50 % (b) 46.2 % (c) 100 % (d) 66.67 % Ans: a
