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What is the significance of scientific laws in physics?
They are well-tested scientific hypotheses that have not been contradicted.
What constitutes a scientific theory?
A large body of well-tested and verified hypotheses about certain aspects of the natural world.
What is the scientific method?
A systematic exploration involving observations, hypotheses, predictions, and experiments.
What is the definition of physics?
The science that deals with matter, energy, motion, and force.
What is the expected approach to scientific hypotheses?
They should be falsifiable and able to be tested through experiments.
What is the role of experimentation in science?
It is the only truth that can validate or invalidate hypotheses and theories.
What are the two astronomical models mentioned in the notes?
Ptolemy's model and Copernicus' model.
What is the definition of science?
Science is a systematic exploration of how the universe works, characterized by factual knowledge gained through the scientific method.
What does physics study?
Physics is the science that deals with matter, energy, motion, and force.
What are the steps of the scientific method?
1. Characterizations (observations, definitions, measurements) 2. Hypotheses (falsifiable explanations) 3. Predictions (logical deductions) 4. Experiments (tests of hypotheses).
What is a scientific law?
A scientific law is a well-tested hypothesis that has not been contradicted, such as Newton's laws of motion.
What is a scientific theory?
A scientific theory is a large body of well-tested and verified hypotheses about certain aspects of the natural world, such as Evolution or Relativity.
What is measurement?
Measurement is the estimation of the magnitude of some attribute of an object, relative to a unit of measurement.
What are the requirements for measurement standards?
Standards must yield consistent results, remain unchanged over time, possess measurable properties, and be readily accessible.
What is the International System of Units (SI)?
The SI is a system of measurement established in 1960, which includes units like meter for length, kilogram for mass, and second for time.
What distinguishes scalar quantities from vector quantities?
Scalar quantities have magnitude only, while vector quantities have both magnitude and direction.
Give examples of scalar quantities.
Examples include mass, volume, speed, and distance.
Give examples of vector quantities.
Examples include velocity, force, acceleration, and position.
How do you add scalar quantities?
Scalar quantities of the same kind are added or subtracted using ordinary arithmetic.
What is the parallelogram law in vector addition?
To add two vectors, draw them tip-to-tail to form a parallelogram; the resultant vector is the diagonal from the origin to the opposite corner.
How do you add two perpendicular vectors?
Use the Pythagorean theorem: R² = X² + Y², where R is the resultant vector.
What is velocity?
Velocity is speed with direction, indicating how fast and in what direction an object is moving.
What is acceleration?
Acceleration is the rate at which the velocity of an object is changing over time.
What is force?
Force is an external influence, such as a push or pull, acting on an object.
What is the significance of scientific attitude?
A scientific attitude involves a willingness to admit that hypotheses can be wrong and to revise them based on new evidence.
What is the role of experiments in the scientific method?
Experiments test hypotheses and predictions to validate or refute scientific theories.
What is the importance of measurement in science?
Measurement is fundamental to the scientific method as it provides the quantitative data necessary for analysis and conclusions.
What is the difference between speed and velocity?
Speed is the magnitude of motion without direction, while velocity includes both speed and direction.
What is the definition of position in physics?
Position refers to where an object is located in space.
What is the relationship between mass and matter?
Mass is the quantity of matter in an object.
What is the significance of the open nature of science?
The open nature of science allows for continuous questioning, testing, and revision of theories based on new evidence.
What is the role of hypotheses in the scientific method?
Hypotheses provide theoretical explanations that can be tested and potentially falsified through experimentation.
What is the definition of a scientific hypothesis?
A scientific hypothesis is a proposed explanation for a phenomenon that can be tested and potentially disproven.
What is the significance of the character of physical law?
Physical laws describe consistent and universal relationships in nature, forming the foundation of scientific understanding.
What is free fall?
An object falls under the influence of gravity alone.
What is the acceleration due to gravity (g) at Earth's surface?
Approximately 9.80 m/s².
How does gravity change with altitude?
Gravity decreases with increasing altitude.
What is the value of g used for approximations in this class?
10 m/s².
What is the formula for speed acquired during free fall?
Speed acquired = acceleration x time = g t.
How is the distance covered by a freely falling object calculated?
d = 1/2 g t².
What does the average velocity of a freely falling object depend on?
It depends on how fast and how long it falls.
What is inertia?
The property of matter to resist changes in motion.
What does Newton's First Law of Motion state?
An object at rest stays at rest, and an object in motion continues in motion at a constant velocity unless acted upon by an external force.
How does mass relate to inertia?
More mass means more inertia.
What happens to a body in motion when external forces are absent?
It moves in a straight line and covers equal distances in equal times.
What is the significance of seat belts in relation to inertia?
They prevent passengers from continuing forward motion when a car suddenly stops.
What are Aristotle's classifications of motion?
Natural motion (objects striving to reach their proper place) and violent motion (caused by external forces).
What is the trajectory of an object in free fall?
It moves downward with increasing speed due to gravity.
What is the relationship between time of fall and speed acquired?
Speed acquired increases linearly with time of fall.
What is the average velocity of an object in free fall after time t?
v = gt.
What is the effect of air resistance on free fall in this course?
Air resistance is neglected for simplification.
What does it mean for an object to be in free fall?
It is accelerating downwards due to gravity only.
What happens to a stationary skater on a level surface?
They remain stationary without a push.
What occurs when a moving skater receives a push?
They change direction or increase speed.
What is the formula for distance covered by a freely falling object based on average velocity?
d = average velocity x time = ((0 + gt)/2) x t.
What is violent motion?
Motion produced by external pushes or pulls on objects, such as wind imposing motion on ships.
Who proposed that Earth is not stationary but orbits the Sun?
Nicolaus Copernicus.
What significant contributions did Galileo Galilei make to physics?
He formulated laws of motion for objects in free fall and supported the heliocentric universe.
What was Galileo's discovery regarding falling objects?
Objects of different masses fall to the ground at the same time in the absence of air resistance.
What concept did Galileo introduce that relates to motion?
The idea of inertia, which states that a moving object needs no external influence to keep moving in the absence of friction.
What are the years of Sir Isaac Newton's life?
1642 - 1727.
What is Newton's First Law of Motion?
An object at rest remains at rest, and an object in motion continues in motion with a constant speed in a straight line unless acted upon by an external force.
What is the definition of force in physics?
A push or a pull that can change an object's state of motion.
What are contact forces?
Forces that involve physical contact between two objects.
What are field forces?
Forces that act through empty space without physical contact, such as gravity and electrostatic forces.
What unit is force measured in?
Newtons (N).
What is net force?
The combination of all forces acting on an object that changes its state of motion.
What does it mean for an object to be in mechanical equilibrium?
When the net force acting on an object is zero, meaning there is no change in its state of motion.
What is static equilibrium?
When an object at rest has no net force acting on it.
What is dynamic equilibrium?
When an object moving in a straight line at a constant speed has no net force acting on it.
If an object is moving with uniform speed on a frictionless surface, how much force is required to maintain that speed?
0 N, as no force is needed to continue uniform motion.
What force is needed to keep a crate moving at a steady speed against a frictional force of 75 N?
A force equal to 75 N is needed to maintain the same steady speed.
What is the significance of Newton's laws of motion?
They describe the relationship between the motion of an object and the forces acting on it.
What is the primary focus of Physics related to motion?
To study how fast things move and how far they move in a given amount of time.
What is the definition of velocity?
Velocity is speed with direction; it describes how fast and in what direction an object is moving.
How is acceleration defined?
Acceleration is how the velocity of an object is changing over time, measured in m/s².
What are the two types of physical quantities related to motion?
Vectors and scalars.
What characterizes a vector quantity?
A vector quantity has both magnitude and direction, such as position, velocity, and force.
What characterizes a scalar quantity?
A scalar quantity has only magnitude, such as mass, volume, and speed.
What is the formula for average speed?
Average speed = total distance / total time.
What is instantaneous speed?
Instantaneous speed is the speed of an object at a specific moment in time, such as what is shown on a speedometer.
What happens to an object's velocity when it is accelerating?
Velocity can change by changing speed, changing direction, or changing both.
What is free fall?
Free fall is when an object falls under the influence of gravity alone, with an acceleration of approximately 9.80 m/s².
What is the relationship between velocity and acceleration when they are in the same direction?
The object is speeding up.
What is the relationship between velocity and acceleration when they are in opposite directions?
The object is slowing down.
What is the formula for the distance fallen by an object in free fall?
Distance = (1/2) g t², where g is the acceleration due to gravity.
What is the significance of the acceleration due to gravity (g)?
It is directed downward and has a magnitude of approximately 9.80 m/s² at the Earth's surface.
Can an object be moving when its acceleration is zero?
Yes, for example, an object sliding on a frictionless flat surface.
Can an object be accelerating even if its instantaneous speed is zero?
Yes, such as when a vertically thrown ball reaches its maximum height.
What does constant velocity imply about an object's motion?
It means the object is moving in a straight line at a constant speed.
What is the SI unit for velocity?
Meters per second (m/s).
What is the SI unit for acceleration?
Meters per second squared (m/s²).
What does it mean for speed to be constant?
Equal distance is covered in equal intervals of time.
How do you determine the components of a vector?
By resolving the vector into its vertical and horizontal components, which are perpendicular to each other.
What is the effect of altitude on the acceleration due to gravity?
g decreases with increasing altitude.
What is the average velocity of an object in free fall from rest after time t?
Average velocity = (0 + gt) / 2.
What is the significance of the thumb rule in acceleration?
It helps to understand how acceleration is calculated based on the change in speed over time.
Mass
Mass is measured in kg.
Weight
Weight is measured in Newton.
Weight Formula
Weight = mg.