Statics and Vector Quantities Quiz

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Questions and Answers

What is the total distance the UniKL Miat student walked on the first and second day if they walked 12 km east and 5 km east?

5 km

12 km

7 km

17 km (correct)

If the UniKL Miat student walked 12 km east on the first day and 5 km west on the second day, what is the magnitude of the resultant vector for the journey?

17 km to the east

7 km to the east (correct)

5 km to the west

12 km to the east

What defines an equilibrant force in a system of forces?

It has a greater magnitude than the resultant.

It acts in the same direction as the resultant force.

It can change the direction of the resultant force.

It is equal in magnitude and opposite in direction to the resultant. (correct)

When resolving a vector in two dimensions, what is the direction of the two component vectors?

They act along two mutually perpendicular directions. Signup and view all the answers

In the context of force equilibrium, what can be said about the magnitude of the equilibrant and the resultant forces?

The equilibrant is equal to the resultant. Signup and view all the answers

What is the expression for the x-component of vector A?

A cos θ Signup and view all the answers

Which expression correctly calculates the magnitude of vector A?

A = √(Ax^2 + Ay^2) Signup and view all the answers

What does tan θ represent in terms of vector components?

Ay / Ax Signup and view all the answers

If vector A has a magnitude of 150 N and an angle of 20°, what is the expression for its y-component Ay?

150 sin 20° Signup and view all the answers

Which of the following represents a negative component of vector B along the x-axis?

Bx Signup and view all the answers

When finding the resultant force of two vectors, which components are combined?

The x-components and y-components separately Signup and view all the answers

For a vector A with a magnitude of 60 N and an angle of 35°, how can the x-component be expressed?

60 cos 35° Signup and view all the answers

Which of the following angles would need to be used for calculating the y-component of vector A at a magnitude of 150 N and an angle of 25°?

25° Signup and view all the answers

What happens to a body when force is applied at the center of gravity?

The body will not rotate. Signup and view all the answers

What is produced when force is applied off the center of gravity?

Torque. Signup and view all the answers

What is essential for an aircraft’s safety in flight regarding the center of gravity?

It must fall within specified limits. Signup and view all the answers

What are the specified limits for the center of gravity of an aircraft?

Longitudinal and lateral limits. Signup and view all the answers

Why is it important to evenly load an aircraft?

To maintain stability during flight. Signup and view all the answers

What can affect the center of gravity in flight?

Fuel usage and passenger movement. Signup and view all the answers

What will happen if the center of gravity limits are exceeded?

The aircraft may become unstable. Signup and view all the answers

What factors contribute to determining the center of gravity of an aircraft?

Equipment, passengers, baggage, cargo, and fuel. Signup and view all the answers

What defines a ‘COUPLE’ in terms of forces?

An arrangement of forces that creates a torque. Signup and view all the answers

What is the resultant moment of a couple also known as?

Torque Signup and view all the answers

What is the function of the centre of gravity (C of G) in flying objects?

To serve as the point of rotation. Signup and view all the answers

How does the centre of gravity affect the stability of an object?

The lower the C of G, the more stable the object. Signup and view all the answers

What can be deduced about an object with a wide base regarding its C of G?

It is more stable due to a lower effective C of G. Signup and view all the answers

In which scenario would an object be least stable?

When it has a narrow base. Signup and view all the answers

What is a characteristic of gravity as a force?

It is a pulling force towards a central point. Signup and view all the answers

Where does the total weight of a body appear to be concentrated?

At the centre of gravity. Signup and view all the answers

What effect does adding detergent to water have on surface tension?

It reduces surface tension. Signup and view all the answers

What is the term for vaporization that occurs at the surface of a liquid at any temperature?

Evaporation Signup and view all the answers

How does surface tension behave in a liquid?

It prevents molecules from escaping. Signup and view all the answers

What phenomenon occurs due to microscopic bubbles in a liquid?

Dissolved air release. Signup and view all the answers

What happens when the molecules in a liquid reach the boiling point?

Some molecules can escape if they have enough energy. Signup and view all the answers

What defines tensile stress in mechanical bodies?

A force that pulls an object apart. Signup and view all the answers

Which example best illustrates compression in materials?

An aircraft rivet holding parts together. Signup and view all the answers

What is the general term for the phase change from liquid to gas?

Vaporization Signup and view all the answers

What is torsion in the context of mechanical stress?

When a material is twisted. Signup and view all the answers

What primarily causes the surface tension of a liquid?

The cohesive forces between liquid molecules. Signup and view all the answers

How does bending affect an aircraft's wing during flight?

It attempts to bend the wing upward. Signup and view all the answers

What occurs to surface tension in a liquid when it is contaminated?

It decreases significantly. Signup and view all the answers

What characterizes shear stress in materials?

It tries to slide an object apart. Signup and view all the answers

In which scenario would torsion typically occur?

When a lever is twisted to lift an object. Signup and view all the answers

Which of the following is NOT a type of stress in mechanical bodies?

Flexion Signup and view all the answers

What is the main purpose of a flexible steel cable in aircraft control systems?

To withstand tensile loads. Signup and view all the answers

Study Notes

Statics

Statics is the study of bodies at rest when forces are balanced.
A force applied to a body causes that body to move in the direction of the applied force. Forces have magnitude (size) and direction.
Some forces require contact between objects (e.g., friction between car tires and the road).
Other forces do not require contact (e.g., force between magnets).
Forces are vector quantities, meaning they have both magnitude and direction.
Work is calculated as force multiplied by the distance the object moves.
One Newton (N) is the force that gives a 1 kg mass an acceleration (or deceleration) of 1 m/s².

Learning Outcomes

Describe statics.
Understand forces, moments, and couples and their representation as vectors.
Define and understand center of gravity.
Grasp the core theory elements.
Explain nature of properties.
Describe pressure & buoyancy in liquids (barometer).

Scalar and Vector Quantities (Cont.)

Scalar quantities are described by a single number (e.g., length, time, temperature, mass, density, volume).
Vector quantities have a number and direction (e.g., force, momentum, velocity, displacement, acceleration).
The magnitude of a vector is its size. The symbol for a vector quantity is often represented as F.

Vector Addition

The final result of a series of displacements is the same as if the particle had undergone a single displacement, called the resultant vector or vector sum.

Forces

A force is anything that tends to cause, stop, or change motion.
Force is measured in Newtons (N).

Vectors in 2 Dimensions

A vector in two dimensions can be resolved into two component vectors acting along perpendicular directions (x and y axis).
The magnitude of a two-dimensional vector is calculated using the equation |A| = √(Ax² + Ay²). The direction of a two-dimensional vector is calculated using the equation tan θ = Ay / Ax.

Component Vectors

Component vectors along x and y axes depend on angle θ. Signs (positive or negative) of components indicate direction relative to the axes.

Example Calculations

Examples are provided to illustrate calculating resultant force of given vectors and solving for unknown forces.

Moments and Couples (Cont.)

A force can cause rotation, the turning effect is the moment of a force.
Moment depends on force magnitude and perpendicular distance (lever arm) from the force to the axis of rotation.
Moment (Nm) equals force magnitude (N) multiplied by perpendicular distance (d).
A force acting through the pivot does not produce rotation.

Moments and Equilibrium

Equilibrium occurs when all forces and moments acting on a body cancel each other.
In equilibrium, the sum of clockwise moments equals the sum of anticlockwise moments for rotation about any point.
Examples involving finding unknown force and pivot location are given.

Nature of Properties

Explains descriptions of strength, stiffness, elasticity, toughness, hardness, brittleness, malleability, and ductility.

Properties of Fluids

Explains descriptions of viscosity, surface tension, evaporation, and boiling point.

Pressure and Buoyancy in Liquids

Pressure is the internal reaction or resistance to a force; pressure (P) = force (F) / area (A). The Sl system for pressure is 1Pa=1 N/m².
Pascal's law states that pressure acts equally in all directions in a fluid.
Atmospheric pressure is the weight of the air above the earth's surface. Standard atmospheric pressure is 1 atmosphere = 760 mmHg = 29.92 inHg = 14.7 lb/in² = 101.3 kPa.
The pressure difference is calculated with p (density of the liquid) x g (gravity) x h.
Buoyancy is the upward force exerted on a submerged object. Archimedes' principle states the buoyant force is equal to the weight of the displaced liquid.
An object will float when the buoyant force is greater than its weight, sink when it is less, and stay still in equilibrium (stuck) if they are equal.

Strain

Stress is the force inside an object caused by an external force.
Strain is the change in dimension or distortion divided by the original dimension, and has no units.
Hooke's law states the strain is proportional to stress when within the elastic limit of the material.

Examples of Stress and Strain

Provide calculation examples to illustrate tensile and compressive strain.

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Description

Test your knowledge on statics, forces, and vector quantities with this quiz. Learn about the principles of forces, moments, and how to calculate work and pressure in liquids. This quiz will help reinforce your understanding of these fundamental concepts in physics.