Moments of Force and Equilibrium: Master Balance and Stability in Biomechanics

Question 1

Define a moment of force.

Accepted Answer

A perpendicular force applied to an object to cause rotation

Answer

A force applied parallel to an object

Answer

A force that causes an object to accelerate

Answer

A force that supports an object against gravity

Question 2

What is the SI unit of a moment of force?

Accepted Answer

Newton-meter (N·m)

Answer

Newton (N)

Answer

Kilogram-meter (kg·m)

Answer

Joule (J)

Question 3

State the principle of moments of equilibrium.

Accepted Answer

A body in equilibrium has zero net force and zero net torque.

Answer

A body in equilibrium has a balanced distribution of mass.

Answer

A body in equilibrium is at rest or moving with constant velocity.

Answer

A body in equilibrium is supported by an equal and opposite force.

Question 4

Describe the relationship between center of mass and stability.

Accepted Answer

Objects with a lower center of mass are more stable.

Answer

Objects with a higher center of mass are less stable.

Answer

The center of mass has no impact on stability.

Answer

Stability is solely determined by the object's weight.

Question 5

Which of the following terms refers to the tendency of a force to cause rotation about a point?

Accepted Answer

Torque

Answer

Moment of inertia

Answer

Angular momentum

Answer

Centripetal force

Question 6

If the clockwise moment acting on a body is 50 Nm and the anticlockwise moment is 30 Nm, what is the resultant moment?

Accepted Answer

20 Nm clockwise

Answer

20 Nm anticlockwise

Answer

80 Nm clockwise

Answer

80 Nm anticlockwise

Question 7

Which of the following does NOT affect the moment of force?

Accepted Answer

Mass of the object

Answer

Magnitude of the force

Answer

Distance from the pivot point

Answer

Angle of application of force

Question 8

What is the SI unit of torque?

Accepted Answer

Newton-meter (Nm)

Answer

Joule (J)

Answer

Watt (W)

Answer

Kilogram-meter (kgm)

Question 9

What is the difference between clockwise and anticlockwise moments?

Accepted Answer

Clockwise moments produce rotation in a clockwise direction, while anticlockwise moments produce rotation in an anticlockwise direction.

Answer

Anticlockwise moments produce rotation in a clockwise direction, while clockwise moments produce rotation in an anticlockwise direction.

Answer

There is no difference between clockwise and anticlockwise moments.

Question 10

Which of the following types of equilibrium occurs when an object returns to its original position after being displaced?

Accepted Answer

Stable equilibrium

Answer

Unstable equilibrium

Answer

Neutral equilibrium

Answer

Dynamic equilibrium

Question 11

What is the key difference between scalar and vector moments of force?

Accepted Answer

Scalar moments have only magnitude, while vector moments have both magnitude and direction.

Answer

Vector moments have only magnitude, while scalar moments have both magnitude and direction.

Answer

There is no difference between scalar and vector moments of force.

Question 12

For an object to be balanced, the turning forces on it need to be equal and opposite.  What do we call this state of balance?

Accepted Answer

Equilibrium

Answer

Continuous rotation

Answer

Force application at the same point

Answer

Unrelated to equilibrium

Question 13

Define the concept of a moment of force.

Accepted Answer

The product of a force and the perpendicular distance from the axis of rotation

Answer

A force applied directly to a rigid body

Answer

The force required to prevent an object from rotating

Answer

The rate of change of angular momentum

Question 14

State the formula for calculating the moment of force.

Accepted Answer

Moment of force = Force x Distance

Answer

Moment of force = Force / Distance

Answer

Moment of force = Distance / Force

Answer

Moment of force = Force x Velocity

Question 15

Enunciate the principle of moments.

Accepted Answer

The algebraic sum of the clockwise moments about a point must equal the algebraic sum of the anticlockwise moments about the same point

Answer

The moment of force is always constant

Answer

The force applied to an object is equal to the moment of force

Answer

The distance from the axis of rotation is irrelevant

Question 16

Calculate the moment of force when a force of 100 N is applied to a lever 2 meters from the pivot point.

Accepted Answer

200 Nm

Answer

50 Nm

Answer

100 Nm

Answer

400 Nm

Question 17

Describe methods for maintaining equilibrium in a biomechanical system.

Accepted Answer

Employing all of the above methods

Answer

Adjusting the center of gravity

Answer

Increasing the base of support

Answer

Utilizing muscle contractions

Question 18

Establish the relationship between moments of force and balance.

Accepted Answer

Moments of force can cause or disrupt balance

Answer

Balance causes moments of force

Answer

Moments of force and balance are independent

Answer

Moments of force have no impact on balance

Question 19

Which of the following scenarios demonstrates equilibrium, where a moment of force is present but no rotation occurs?

Accepted Answer

A gymnast holding a static handstand

Answer

A tennis player serving the ball

Answer

A swimmer executing a flip turn

Question 20

Two athletes, one with a shorter lever arm (distance from pivot point to force application) and one with a longer lever arm, apply equal force to a weight. Which athlete produces a greater moment of force?

Accepted Answer

The athlete with the longer lever arm

Answer

The outcome depends on the weight of the object being lifted

Answer

The athlete with the shorter lever arm

Answer

Both athletes produce the same moment of force

Question 21

A gymnast performs a handstand. Describe the primary moment of force acting on the gymnast's body:

Accepted Answer

The moment of force created by the gymnast's weight acting about the point of contact with the hands

Answer

The moment of force generated by the gymnast's muscle force acting on the joints

Question 22

A sprinter leans forward during acceleration. What is the main purpose of this action?

Accepted Answer

To lower the center of mass and enhance stability

Answer

To increase the moment of inertia and enhance power

Answer

To minimize air resistance and improve speed

Question 23

A high jumper uses a pole to assist in their jump. Which principle of moments explains how the pole allows the jumper to achieve greater height?

Accepted Answer

By using the pole as a lever, the jumper can amplify the moment of force and jump higher

Answer

The pole supplies additional momentum for the jump

Answer

The pole lessens air resistance, facilitating a smoother ascent

Question 24

A diver executes a somersault in mid-air. How does the diver manage to maintain equilibrium during the rotation?

Accepted Answer

By controlling body mass distribution to maintain a stable center of mass

Answer

By relying on the centrifugal force generated by the rotation

Answer

By harnessing air resistance to decelerate the rotation

Question 25

A gymnast performs a cartwheel. What primary factor affects the speed of the rotation?

Accepted Answer

Moment of inertia of the gymnast's body

Answer

Force exerted by the gymnast's legs

Answer

Air resistance encountered by the gymnast

Answer

Angle of the cartwheel

Question 26

A long jumper aims to extend their jump distance. What is the most effective approach?

Accepted Answer

Enhance horizontal velocity at take-off and retain a horizontal body position throughout the jump

Answer

Increase vertical velocity at take-off and sustain an upright body position