Net force Knowledge-Based Download PDF

Questions

1. 1.

   An elevator descends vertically while slowing down to a stop. What is the direction of the net force acting on the elevator during this motion?

   • A) Directed vertically upward
   • B) Directed vertically downward
   • C) Equal to zero
   • D) Directed horizontally
2. 2.

   Two forces act along the same line on an object such that their net force is 20 N when they point in the same direction and 8 N when they point in opposite directions. What is the magnitude of the larger force?

   • A) 6 N
   • B) 10 N
   • C) 14 N
   • D) 28 N
3. 3.

   An object is subject to several concurrent forces whose vector sum is zero. Which of the following states of motion is impossible for this object?

   • A) Remaining at rest
   • B) Moving at a constant speed along a curved path
   • C) Moving along a straight line at a constant speed
   • D) Maintaining a constant velocity
4. 4.

   Which of the following describes a situation in which the net force acting on the object is non-zero?

   • A) An airplane cruising along a straight horizontal path at constant speed
   • B) A framed picture hanging completely motionless on a wall
   • C) A car rounding a level circular curve at constant speed
   • D) A skydiver descending vertically at a constant terminal velocity
5. 5.

   Which condition must be satisfied for two concurrent forces acting on an object to produce a net force of zero?

   • A) The forces must have equal magnitudes and act in perpendicular directions.
   • B) The forces must have equal magnitudes and act in opposite directions along the same line.
   • C) The forces must have unequal magnitudes and act in opposite directions along the same line.
   • D) The forces must have equal magnitudes and act in the same direction along the same line.
6. 6.

   A heavy box rests on a horizontal floor. A person exerts a horizontal force of 85 N on the box, but the box remains at rest. What is the magnitude of the net force acting on the box?

   • A) 85 N
   • B) 0 N
   • C) 42.5 N
   • D) 170 N
7. 7.

   Which of the following correctly defines the net force acting on an object?

   • A) The scalar sum of the magnitudes of all forces acting on the object
   • B) The vector sum of all individual forces acting on the object
   • C) The magnitude of the single largest force applied to the object
   • D) The difference between the largest force and the smallest force acting on the object
8. 8.

   Two forces act concurrently on an object: $\vec{F}_1 = (9\hat{\imath} - 4\hat{\jmath})\text{ N}$ and $\vec{F}_2 = (-2\hat{\imath} + 7\hat{\jmath})\text{ N}$. What is the net force acting on the object?

   • A) $(11\hat{\imath} + 3\hat{\jmath})\text{ N}$
   • B) $(7\hat{\imath} - 11\hat{\jmath})\text{ N}$
   • C) $(7\hat{\imath} + 3\hat{\jmath})\text{ N}$
   • D) $(11\hat{\imath} + 11\hat{\jmath})\text{ N}$
9. 9.

   Two forces of constant, non-zero magnitudes act concurrently on an object. As the angle between the directions of these two forces increases from 0° to 180°, how does the magnitude of the net force acting on the object change?

   • A) It decreases continuously from a maximum value to a minimum value.
   • B) It increases continuously from a minimum value to a maximum value.
   • C) It remains constant because the individual force magnitudes do not change.
   • D) It increases to a maximum at 90° and then decreases toward 180°.
10. 10.

    Three coplanar forces of equal magnitude $F$ act concurrently on an object such that the angle between any two adjacent force vectors is 120°. What is the magnitude of the net force acting on the object?

    • A) 0
    • B) $F$
    • C) $\sqrt{3}F$
    • D) $3F$
11. 11.

    Two forces with magnitudes of 12 N and 5 N act concurrently on an object. Which of the following values could be the magnitude of the net force acting on the object?

    • A) 4 N
    • B) 13 N
    • C) 19 N
    • D) 25 N
12. 12.

    An object experiences two vertical forces: a 45 N force directed upward and a 70 N force directed downward. What third vertical force must be applied to the object so that the net force acting on it is zero?

    • A) 115 N directed upward
    • B) 25 N directed downward
    • C) 25 N directed upward
    • D) 115 N directed downward
13. 13.

    Two perpendicular forces with magnitudes of 6 N and 8 N act simultaneously on an object. What is the magnitude of the net force acting on the object?

    • A) 2 N
    • B) 10 N
    • C) 14 N
    • D) 48 N
14. 14.

    Three horizontal forces act on an object: 15 N to the right, 25 N to the right, and 18 N to the left. What is the net force acting on the object?

    • A) 58 N to the right
    • B) 22 N to the left
    • C) 22 N to the right
    • D) 8 N to the left
15. 15.

    A crate on a flat surface experiences a horizontal pulling force of 35 N to the east and a horizontal frictional force of 12 N to the west. What is the magnitude and direction of the net horizontal force acting on the crate?

    • A) 23 N to the east
    • B) 47 N to the east
    • C) 23 N to the west
    • D) 47 N to the west