Equilibrium of Forces MCQs
1. How is the weight of the aeroplane flying in the air balanced?
a) The weight is balanced because of the force due to the pressure difference between the upper and lower surfaces of the wings created by different airspeeds on the surfaces.
b) The weight is balanced due to the vertical component of the thrust created by air currents striking the lower surface of the wings
c) The weight is balanced due to the force produced when the reactions of gases are ejected by the revolving propellor.
d) Upthrust of the air which will be equal to the weight of the air having the same volume as the plane
Answer: (a) The weight is balanced because of the force due to the pressure difference between the upper and lower surfaces of the wings created by different airspeeds on the surfaces.
2. Which of the following is true when a body is stationary?
a) The force acting on it is not in contact with it
b) The body is in vacuum
c) There is no force acting on it
d) The combination of forces acting on it balance each other
Answer: (d) The combination of forces acting on it balance each other
3. Two forces with magnitude F have the resultant of same magnitude F. What is the angle between the forces?
a) 450
b) 600
c) 1200
d) 1500
Answer: (c) 1200
4. In which direction should the force be applied to balance a force in the direction of North-East direction?
a) South
b) West
c) South-West
d) North-East
Answer: (c) South-West
5. Among the following which cannot be a resultant force of 5 N and 10 N?
a) 4 N
b) 5 N
c) 8 N
d) 12 N
Answer: (a) 4 N
6. The resultant of the two forces are perpendicular to the smaller of the two forces. The magnitude of one of the forces is double the magnitude of the other force. What is the angle between the forces?
a) 600
b) 900
c) 1200
d) 1500
Answer: (c) 1200
7. Two blocks connected to each other by a string is hung to the ceiling by connecting another string to the upper block. When a force F is applied on the string, it produces an acceleration of 2 m/s2. If T and T’ are the tensions in two parts of the string, then which of the following is true?
a) T = 70.8 N and T’= 47.2 N
b) T = 70.8 N and T’= 0
c) T = 70.8 N and T’= 58.8 N
d) T = 58.8 N and T’= 47.2 N
Answer: (a) T = 70.8 N and T’= 47.2 N
8. Consider the blocks shown in the diagram to be pushed against a frictionless table by a constant force. Following statements are said about the blocks:
All blocks move with the same acceleration
The net force on all the blocks is the same
Which of these statements is true?
a) Both A and B
b) Neither A and B
c) Only A
d) Only B
Answer: (c) Only A
