Force System Resultants topics include: Moment of a force and couple, moment of a force on simplified axis, simple distributed loading, force and couple system simplification. A force system resultant is a representative force that has the same effect on a body as the group of forces it replaces. It is the simplest force that can replace the original forces system without changing its external effect on a rigid body.  The resultant force is the sum of all the vector forces being applied to an object. It is the total amount of force acting on the object or body along with the direction of... Show more

Force System Resultants topics include: Moment of a force and couple, moment of a force on simplified axis, simple distributed loading, force and couple system simplification.

A force system resultant is a representative force that has the same effect on a body as the group of forces it replaces. It is the simplest force that can replace the original forces system without changing its external effect on a rigid body. 
The resultant force is the sum of all the vector forces being applied to an object. It is the total amount of force acting on the object or body along with the direction of the body. 
The resultant force is zero when the object is at rest or it is traveling with the same velocity as the object. 
The magnitude of the resultant force is equal to the total area A under the loading diagram for length L. 
The resultant of a noncoplanar force system is a force R and a couple M, where R = ∑ F, the vector sum of all forces of the system. 

Examples of force systems include:
Forces system on lifting a weight with a pulley system
System on a balanced plank at a pivot 

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Engineering Mechanics Practice Test: Force System Resultants

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25 Questions

1. If any force is applied in the direction of the positive x-axis, and there are three different point on which the moment of this force is to be calculated. Then if these three points are on the positive side of the y-axis with varying distance, then what will be the direction of the moment caused by the force to the individual point?

Towards positive x-axisTowards positive z-axisTowards positive y-axisTowards negative z-axis

2. What does the moment of the force measure?

The tendency of rotation of the body along any axisThe moment of inertia of the body about any axisThe total work is done on the body by the forceThe couple moment produced by the single force acting on the body

3. The resultant force is equal to the _______ of all the forces.

ProductSubtractionSumDivision

4. In triangle distributed loading, the loading at any distance can be easily found by using which of the following trigonometry function?

CosineTangentSineSine inverse

5. The couple is simplified easily with the help of left hand rule. But the forces simplification is not possible as there is no such system of rules so that the forces can be simplified.

The first part of the statement is false and other part is trueThe first part of the statement is false and other part is false tooThe first part of the statement is true and other part is falseThe first part of the statement is true and other part is true too

6. The system of the collinear and the parallel force are simplified as ______________

The simplification is usually done by not considering the directions of the bothThe simplified collinear force system gives us a net force and the parallel force system gives us a simplified force, and then we add it vectoriallySuch simplification is not possibleThe simplification is done by considering the rotations only

7. Which of the following is true?

Total moment of various forces acting on the body is the vector sum of all momentsTotal moment of various forces acting on the body is always zeroTotal moment of various forces acting on the body is the vector sum of all moments which is perpendicular to each other forcesTotal moment of various forces acting on the body is the algebraic sum of all moments

8. The calculation of the moment about the axis and the moment about any point by a force applied on the body are different from each other.

FalseMaybeTrueDon't Know

9. The type of reduction of the loading is different for the uniformly distributed and the non-uniformly.

TrueMaybeDon't KnowFalse

10. How far from the shaft at P a 200N vertical force must act so as to create the same moment as produced by the 75N, at P?

0m0.6m1.2m1.125m

11. In the collinear force system, a net force is being made after all the simplification done on all the forces.

Don't KnowTrueMaybeFalse

12. If two forces magnitude F each are acting in the Cartesian coordinate and are acting at the points A(3,3) and B(-3,3). They are heading towards negative z direction and positive z direction respectively. The distance between them is given as r. The radius vectors of the force at A and B are Ra and Rb respectively. Then the moment is given as:

(Ra-Rb)xF(Rb-Ra)xF(Rb-Ra).F(Ra-Rb).F

13. The resultant force acting, of the uniformly distributed loading, is dependent on:

The distance of the supports between themVertical distanceAreaLength of the supports

14. In the calculation of the moment of the force about the axis, the cross product table, i.e. the 3X3 matrix which is made for doing the cross product having 3 rows, contains three elements. Which are they from top to bottom?

Axis coordinates, force coordinates, and the point coordinatesForce coordinates, point coordinates, and the axis coordinatesPoint coordinates, axis coordinates, and the force coordinatesAxis coordinates, point coordinates, and the force coordinates

15. If any external force also is applied on the distributed loading then?

The net force will act on the base of the loading horizontallyThe net force will not to be considered, there would be a net force of the distribution, rest will be the external forcesThe net load will not be formed as all the forces will be cancelledThe net force will act at the centroid of the structure only

16. The ___________ forces do not cause the rotation.

ParallelNon-ParallelNon-concurrentConcurrent

17. The basic way of getting the direction of the moment caused by the force is:

The use of right hand rule with thumb giving the direction of the momentThe use of left hand rule with thumb giving the direction of the momentThe use of left hand rule with forefinger giving the direction of the momentThe use of right hand rule with forefinger giving the direction of the moment

18. In the equation A.(rxF) the r is heading from ______________ and ending at _____________

Axis of rotation, Force vectorAxis of rotation, Force vector’s point of action on the bodyForce vector’s point of action on the body, Axis of rotationForce vector, Axis of rotation

19. The resultant couple moment is ____________ sum of various couples acting on the body.

ScalarDotVectorScalar Triple

20. If a force applied at any point in its line of action and is still creating the same moment about any fixed point say P, then the force is said to be a sliding vector. What is the name of this property?

Distributive propertyNegative associative propertyAssociative propertyPrinciple transmissibility of the force

21. Find the total resultant force acting in the given figure consisting of a beam with various sections.

461N350N250N300N

22. A couple moment is a _______ vector.

FreeScalarGradientDel

23. What does FLsinθ means/ represent for the moment (M) of the force (F) acting on the body at a distance L from the axis of the rotation?

Unit vector of the moment vectorThe perpendicular distance of the force from the axis of rotationThe magnitude of the moment caused by the force on the bodyThe direction vector of the moment

24. If you are getting to know about the direction of the moment caused by the force applied on the body by using your wrist and curling it in the direction of the rotation then which of the following is not right?

The thumb represents the direction of the momentThe direction in which you curl your wrist is towards the direction of the distance from point of contact of force to the axis of rotation.The fingers represent the direction of the forceThe thumb represents the direction of the force

25. The couple is simplified easily with the help of right hand rule. But the forces simplification is not possible as there is no such system of rules so that the forces can be simplified.

The first part of the statement is true and another part is falseThe first part of the statement is false and another part is false tooThe first part of the statement is false and another part is trueThe first part of the statement is true and another part is true too