unit 1 of basic electronics of pune university sem I of FEFull description
Tema primero del estudio
ehv ac and dc notes
Department of Mechanical Engineering 15ME205-ENGINEERING MECHANICS STATICS Unit -1 -BASIC CONCEPT AND FORCE SYSTEM
1. Mechanics of rigid body is the study of a) Strength of material b) Theory of elasticity c) Theory of Plasticity d) Statics and dynamics. 2. A train is moving from one station to another station is under observation for the kinematic study do you assume the train is a a) Rigid body b) Particle c) Equilibrium of particle. d) Equilibrium of rigid body. 3. The dimension for force is a) MLT-2 b) ML-1T-1 c) ML2T d) ML-2T-2 4. Which of the following is not the unit of Power? a) Kw(Kilowatt) b) Hp(Horse power) c) Kcal/sec d) Kcal/kg sec. 5. If you tie a string around a 2 pounds bag of sugar and hang it on a weighing scale a spring in the scale stretches until the scale read 2 Pounds. It can be represented mathematically a) F=9N b) F=2lb c) F=0 d) Ʃf=0
6. 5N
10N
The net force will be
a) +5N b) -5N c) +15N d) -15N 7. If the resultant of two forces P and Q is R.If Q is doubled ,the new resultant is perpendicular to P ,then a) P=Q b) Q=R c) Q=2R d) Q=2P 8. Any object whose dimension if not involved in analysis then it is assumed as a) Rigid body b) Deformable body c) Plastic body d) Particle. 9. An Implication of newtons first law is that a) The total momentum of the body is conserved. b) The linear and angular momentums of the body are conserved separately. c) Only the linear momentum of the body is conserved. d) A rigid body will tend to rotate if a force is applied at a point other than the centre of mass of the body. 10. Which is the correct statement about the law of polygon of forces? a) If any number of forces acting at a point can be represented by the sides. b) Polygons taken in order, then the forces are in equilibrium. c) If any number of forces acting at a point can be represented in direction and magnitude by the sides of a polygon, then the forces are in equilibrium. d) If a polygon representing forces acting at a point is closed then forces are in equilibrium. 11. Concurrent forces are those forces whose lines of action a) Meet on the same line b) Meet at one point. c) Meet on the same plane d) Lie on the same plane.
12. For finding the resultant of the general force systems we use _____________ equation. a) One b) Two c) Three
d) Four. 13. A single force which replace the given force system having the same effect is called __________ a) Equilibriant b) Resultant c) Equivalent d) Equilibrium. 14. The forces exerted by chairs arranged in an auditorium is a) coplanar parallel system b) coplanar concurrent system c) non-coplanar parallel system d) coplanar collinear system 15. The forces, which meet at one point, but their lines of action do not lie in a plane, are called a) coplanar non-concurrent forces b) non-coplanar non-concurrent forces c) non-coplanar concurrent forces d) Intersecting forces. 16. At equilibrium condition ___ becomes zero. a) equilibrant b) summation of horizontal components c) summation of vertical components d) Resultant. 17. What type of force exerted forces act in see –saw when 2 children’s are sitting? a) Coplanar Parallel force system b) Non coplanar parallel force system c) Non -Coplanar collinear force system d) Coplanar non Parallel force system 18. What type of force system exerted as shown in fig ?
a) Coplanar Parallel force system b) Non coplanar parallel force system c) Non -Coplanar collinear force system d) Coplanar non Parallel force system
19. Example for collinear force system. a) shooting gun b) throwing cricket ball c) travelling in lift d) travelling in bus. 20. What type of force system is exerted in the tripod stand of a video camera ?
a) b) c) d)
Coplanar concurrent force system Non coplanar concurrent force system Non -Coplanar non concurrent force system Coplanar non concurrent force system.
21. If two forces P and Q act at an angle θ ,the resultant of these two forces would make an angle with P Such that a) tan α = Q Sinθ / (P-Q sinθ) b) tan α = P Sinθ / (P+Q sinθ) c) tan α = Q Sinθ / (P+Q Cosθ) d) tan α = Q Sinθ / (P-PCosθ) 22. If the maximum and minimum resultant forces of two forces acting on a particle are 40 kN and 10 kN respectively, then the two forces in question would be a) 25 kN and 15 kN. b) 20 kN and 20 kN. c) 20 kN and 10 kN. d) 20 kN and 5 kN.
23.
Find the magnitude and direction of the resultant force. a) b) c) d)
24. If two forces each equal to P in magnitude act at right angles, their effect may be neutralized by a third force acting along their bisector in opposite direction whose magnitude is equal to a) 2P b) c) d) 25. In concurrent force system if resultant is horizontal then a) Ʃfx=0 b) Ʃfy=0 c) Ʃm=0 d) R=0 26. A body is acted upon by a force system. It can in general be brought to equilibrium by the application of a) A Force acting on a suitable point on the body. b) A force acting anywhere along a suitable line. c) A force along a suitable line and a moment along the direction of force. d) A wrench acting anywhere on the body. 27. If the sum of all forces acting on a body is zero, it may be concluded that the body a) Must be in equilibrium. b) Cannot be in equilibrium c) May be in equilibrium provided the forces are concurrent. d) May be in equilibrium provided the forces are parallel.
28. A rigid must a) b) c) d)
body is in equilibrium under the action of three forces.It implies that the forces Be concurrent Be coplanar Pass through centre of mass Either be coplanar or concurrent.
29. If point A is in equilibrium under the action of the applied forces, the values of tension TAB and TAC are respectively
a) b) c) d)
520 N and 300 N 300 N and 520 N 450 N and 150 N 150 N and 450 N
30. Determine the magnitude of the x and y components of the 2—kN force
a) b) c) d)
Fx = -1.414 kN, Fy = -1.414 kN Fx = -1.000 kN, Fy = -1.732 kN Fx = -1.732 kN, Fy = -1.000 kN Fx = -4.000 kN, Fy = -2.312 Kn
Two Marks: 1. Classify the two types of engineering mechanics. 2. Difference between particle and rigid body. 3. Mention the idealization of mechanics used to simplify the problem without affecting the actual results.
4. State parallelogram law of forces. 5. State triangle law of forces. 6. State newtons first law. 7. State newtons third law. 8. Define principle of transmissibility. 9. Illustrate with neat sketch the characteristic of force. 10. Classify the two types of force system. 11. Identify type of force system involved as shown in fig :
12. Cite examples for concurrent and collinear force system. 13. Indicate the importance of term “Resultant force and Resolution of force ’’. 14. The resultant of two forces has magnitude 20N. One of the forces has magnitude 20√3N making an angle of 30° with the resultant? What is the magnitude of the other force? 15. A body is acted by two forces 50N acting due to east and 100N acting 50ᵒ north of east. Find the resultant of these forces by parallelogram law of forces. 16. Recall the term resolution of forces.
17. Indicate the condition applied for a coplanar concurrent system of forces for an equilibrium body. 18. Resolve F1 into components along the u and axes and determine the magnitudes of these components.
19. Determine the x and y components of 80 N and 120 N of the forces as shown.
20. Illustrate with neat sketch the concept of the term “equilibrium”.
12 Marks Questions:
1. The truck is to be towed using two ropes. Determine the magnitudes of forces FA and FB acting on each rope in order to develop a resultant force of 950 N directed along the positive x axis. Set θ = 500.
2. Two forces are applied at point B of beam AB. Determine the magnitude and direction of their resultant using (a) the parallelogram law, (b) the triangle rule. (6 Marks)
3. A stake is being pulled out of the ground by means of two ropes as shown in figure. Knowing that α = 300, determine by trigonometry (a) the magnitude of the force P so that the resultant force exerted on the stake is vertical, and (b) the corresponding magnitude of the resultant.
4. If FB = 2 kN and the resultant force acts along the positive u axis, determine the magnitude of the resultant force and the angle θ. (6 Marks)
5. The four coplanar forces acting at a point as shown. Determine the resultant in magnitude and direction.
156 N
0
10 0
0
3 252 N
104N
24
90 228N
6. If the magnitude of the resultant force acting on the eyebolt is 600 N and its direction measured clockwise from the positive x axis is θ = 300, determine the magnitude of F1and the angle .
7. Knowing that α = 350 , determine the resultant of the three forces shown
8. Knowing that the tension in rope AC is 365 N, determine the resultant of the three forces exerted at point C of post BC.
