Equilibrium of concurrent forces - One Line Questions
1.
In Lami's theorem, if the angles between the forces are 90°, 120°, and 150°, what is the ratio of the magnitudes of the forces? —
1 : √3 : 2
2.
A weight of 10 N is suspended by two strings making angles 30° and 60° with the vertical. What are the tensions in the strings if the system is in equilibrium? —
5 N and 5 N
3.
Consider a particle in equilibrium under the action of three forces. If the angle between two forces is 90 degrees, and the angle between the first force and the third force is 150 degrees, what is the angle between the second and third force? —
120 degrees
4.
A particle is acted upon by three forces: 3 N along the positive x-axis, 4 N along the positive y-axis, and F N along the negative x-axis. For equilibrium, what is the magnitude and direction of F? —
3 N along the negative x-axis
5.
Three concurrent forces of magnitudes F1, F2, and F3 are in equilibrium. If F1 = 5 N and F2 = 12 N, what is the possible magnitude of F3? —
Any value between 7 N and 17 N
6.
A system of concurrent forces is in equilibrium. If the forces are represented by vectors, their vector sum must be: —
The zero vector
7.
A body is in equilibrium. This implies that the net external force acting on it is: —
Always zero.
8.
A body is acted upon by three forces. If the body is in equilibrium, it means that the body is: —
At rest or moving with constant velocity.
9.
If two concurrent forces are acting on a body, for equilibrium, they must be: —
Equal in magnitude and opposite in direction.
10.
If a particle is in equilibrium under the action of two forces, F1 and F2, what is the relationship between their magnitudes and directions? —
Equal magnitudes, opposite directions.
11.
A block is resting on a horizontal surface. The forces acting on it are its weight, the normal reaction from the surface, and possibly other forces. For the block to be in equilibrium, the vector sum of all these forces must be: —
Zero
12.
Consider a body in equilibrium. If a new force is added to the system, for the body to remain in equilibrium, the new force must be: —
Zero.
13.
A sign is hung from a pole by two ropes. The weight of the sign acts downwards. The tensions in the two ropes are concurrent forces. For the sign to be in equilibrium, the vector sum of the tensions and the weight must be: —
Zero
14.
If a particle is subjected to forces F1, F2, and F3, and it is in equilibrium, then F1 + F2 + F3 = ? —
0 (zero vector)
15.
In Lami's Theorem, if two forces are perpendicular to each other, and the third force makes an angle θ with one of them, what is the relation between the forces? —
F1/sin(90) = F2/sin(θ) = F3/sin(90+θ)
16.
If a particle is in equilibrium under the action of forces F1 and F2, then F1 = ? —
-F2
17.
A lamp is suspended by means of a string. The forces acting on the lamp are its weight and the tension in the string. For the lamp to be in equilibrium, the tension must be: —
Equal to the weight and acting upwards.
18.
A system of concurrent forces is in equilibrium. If we add a new force that is equal in magnitude and opposite in direction to the resultant of the original forces, the system will then be: —
In equilibrium.
19.
A system of concurrent forces is in equilibrium. If we consider a closed polygon formed by representing these forces as vectors head-to-tail, what can be said about the polygon? —
It is a closed polygon.
20.
If three non-coplanar concurrent forces are in equilibrium, what can be said about their vector sum? —
It is zero.
21.
If a system of concurrent forces is in equilibrium, the resultant force is: —
Zero
22.
If a body is in equilibrium, its acceleration is: —
Zero
23.
Consider a system of forces in equilibrium. If we resolve all forces along any arbitrary axis, the algebraic sum of their components along that axis will be: —
Zero
24.
If a system of concurrent forces is in equilibrium, what is the net change in momentum of a particle acted upon by these forces over any time interval? —
Zero
25.
If a particle is in equilibrium, the rate of change of its linear momentum is: —
Zero
26.
Which of the following is a necessary condition for a particle to be in equilibrium? —
Net force is zero.
27.
Which principle states that if a body is in equilibrium under the action of three forces, then each force is proportional to the sine of the angle between the other two? —
Lami's Theorem
28.
Lami's Theorem is a consequence of which fundamental law of motion? —
Newton's First Law
29.
Three forces P, Q, and R are acting at a point. For equilibrium, the resultant of P and Q must be equal and opposite to: —
R
30.
If three concurrent forces P, Q, and R are in equilibrium, which of the following statements is true? —
The vector sum P + Q + R = 0.
31.
According to Lami's Theorem, if three concurrent forces P, Q, and R are in equilibrium, then which relation holds true? —
P/sin(α) = Q/sin(β) = R/sin(γ)
32.
If a system of concurrent forces is in equilibrium, then the work done by these forces when the point of application undergoes a small displacement is: —
Zero
33.
A system of forces is in equilibrium. If we remove one of the forces, the system will: —
No longer be in equilibrium.
34.
What is the condition for a system of concurrent forces to be in equilibrium in terms of components? —
Sum of components along x-axis = 0, y-axis = 0, z-axis = 0.
35.
Consider a scenario where a ladder is leaning against a wall. The forces acting on the ladder are weight, normal force from the ground, friction from the ground, and normal force from the wall. For the ladder to be in equilibrium, what conditions must be met? —
Sum of vertical forces = 0, sum of horizontal forces = 0, and net torque = 0.
36.
A body is acted upon by three concurrent forces of magnitudes 3 N, 4 N, and 5 N. If the body is in equilibrium, what can be said about the angles between these forces? —
The forces form a right-angled triangle.
37.
In Lami's Theorem, what do α, β, and γ represent? —
The angles opposite to the forces.
38.
In the context of equilibrium of concurrent forces, what does 'concurrent' imply? —
The forces act at the same point.
39.
Three concurrent forces of magnitudes 5 N, 12 N, and 13 N are acting on a particle. If the particle is in equilibrium, what can be concluded? —
The forces form a right-angled triangle.
40.
Consider a particle at rest. If it is subjected to two forces, what must be true for it to remain at rest? —
The forces must be equal in magnitude and opposite in direction.
41.
In Lami's Theorem, the angles α, β, and γ are measured between: —
The lines of action of the forces.
42.
What is the condition for a system of concurrent forces to be in equilibrium? —
The vector sum of all forces acting on the system is zero.
43.
Which of the following statements is NOT true for a system of concurrent forces in equilibrium? —
The net torque about any point is zero.
44.
Consider three concurrent forces in equilibrium. If one force is doubled, what must happen to the other forces to maintain equilibrium? —
Their magnitudes and/or directions must change.
45.
Lami's Theorem applies to a system of concurrent forces in equilibrium. What is the minimum number of concurrent forces required for Lami's Theorem to be applicable? —
Three
46.
If the resultant of a system of concurrent forces is zero, the system is said to be in: —
Equilibrium
47.
A particle is subjected to two forces, 5 N and 3 N. Can the particle be in equilibrium? —
Yes, if they are in opposite directions and equal.
48.
If a particle is in equilibrium, and one of the forces acting on it is removed, the remaining forces will have a resultant equal to: —
The negative of the removed force
49.
If a particle is in equilibrium, and we apply a force F to it, the particle will start to move if F is: —
Non-zero