Physics Flashcards
Define Motion
An object is in motion if it changes position with respect to time and with respect to a reference point
Define Displacement
The shortest possible path from one point to another in a specific direction
Define density
Amount of Mass present per unit volume
How do forces influence the motion of an object?
Forces cause changes in the state of motion, either by initiating movement, altering speed, or changing direction.
Define speed
Ratio of total distance traveled by an object and the total time taken
Is speed scalar or vector?
Scalar
Define Instantaneous speed
Distance travelled by a body in a very short interval of time
Define Velocity and state what type of quantity is it
Displacement of a body in unit time or the rate at which displacement occurs, a vector quantity
Define acceleration
Change in velocity of the body in unit time
How does a distance-time graph depict an object’s speed
the object’s speed is shown by the slope - steeper slopes indicate higher speeds
In what ways does a speed-time graph illustrate an object’s acceleration or deceleration, and how is it connected to changes in speed?
A speed-time graph illustrates an object’s acceleration or deceleration; a straight line denotes constant acceleration, while a curve indicates changing acceleration
Explain how an acceleration-time graph displays changes in an object’s speed and the relationship between acceleration and motion.
An acceleration-time graph displays changes in an object’s speed. a horizontal line represents constant acceleration, while slopes indicate changes in acceleration.
What is terminal Velocity/Speed
A constant velocity with which a body falls down under the influence of gravitational force and fluid resistance
Explain the role of friction in the context of motion.
Friction opposes motion, affecting an object’s speed, causing heat, and enabling control in various applications.
What role does air resistance play in the motion of objects?
Air resistance prevents the motion of objects through the air, affecting their speed and trajectory.
What is normal reaction?
Force acting on a body when its present on top of a surface. Does not exist if the body is not present on a surface
What is gravitational force?
Gravitational force is the attraction between objects with mass, pulling them toward each other.
What is a restoring force?
any force that always acts to pull a body back toward equilibrium
What is mass equilibrium?
Point where spring force and gravitational force is the same
Hooke’s Law
Within the elastic limit, the restoring force is directly proportional to the displacement of the body, from its equilibrium position.
What is tension
Force which is transmitted through a rope, chain, wire when pulled by forces acting on opposite sides
Hooke’s Law equation
F = -kx (F = restoring force, -k = Spring constant, x = Displacement from equilibrium position)
What is friction?
The force which opposes relative motion. if there is no applied force on a body, the frictional force will also be zero.
What is static friction?
Friction that acts on objects that are at rest. Increases with applied force
What is dynamic friction?
present between two objects which are in relative motion. this value is less than static friciton.
Why does firction exist?
Irregularities between the objects and surface. There is oging to be an interlock
dynamic friction is also known as
Kinetic energy
Why does the statsic friction drop after reaching limiting friction when force is applied?
No more irregularities between the surfaces and objects causing it to move
Increase in mass = what happnes to firction
Increase in friction. Hence a greater limiting and dyanmic friction
What is the max possible value of static friction called?
Limiting Friction, when the applied force exceeds this value, the body starts to move.
Max possible value of statsic frcition is called:
Limiting Friction
What is Net force
Total force excerted on a body, Vector quantity
What is momentum
Product of Mass and Velocity, vector quantity, SI unit - kgms^-1
What is the law of inertia or Newton’s first law
A body continues to remain in a state of rest or in a state of motion until & unless an external force acts on it
What is Newton’s second law
The net force acting on a body is directly proportinal to the rate of change in momentum
What is Newton’s third law
For every action there is an equal and opposite reaction if action is on one body, the reaction will be on the other
what is the law of conservation of momentum?
For an isolated system of objects, the momentum before collision is equal to the total after the collision
How does the law of conservation of momentum apply to road collisions?
In collisions, total momentum before and after impact remains constant unless external forces act in it.
Explain the concept of moments concerning levers.
levers depend on the force applied and the distance from the pivot point. direction of movement is based on the points from which the input and output forces are being exerted
Define moments in physics
The rotational turning effect caused by a force on a body on its axis on a pivot point
To get the biggest moment possible, what 2 things could you do?
- Increase the distance from the pivot
- Increase force applied
If the input & output force are on different sides of the pivot, then they will act in which direction?
different directions to each other
If the input & output force are on the same sides of the pivot, then they will act in which direction
same direction to each other
What is torque
Measurement of the force which causes something to rotate around a pivot
What is Impulse
Change in momentum
Define the centre of mass and its significance in physics.
The centre of mass is the point where the mass of an object is concentrated, which helps predict the motion of the object
How is pressure defined and calculated in a physics context?
pressure is the perpendicular force present per unit area
calculated by a ratio perpendicular force (F) over an area of cross-section (A)
Pressure and area are what type of relationship
inversely related (pressure increases, area decreases)
What is the relationship between work, power, and efficiency in physics?
Work is said to be done if a force displaces an object in the direction of the force applied
power measures the rate at which work is done,
efficiency measures how effectively work is performed by finding the useful energy output from the total energy input
What is collisions
2 objects are said to collide with each other if there is a change in the state of motion of one object because of the other
What are the seven fundamental physical quantities in the International System of Units (SI)?
length,
mass,
time,
electric current,
temperature,
amount of substance, luminous intensity.
Why are fundamental physical quantities crucial in physics?
Fundamental physical quantities form the basis for measuring and describing all other physical phenomena in the universe.
Explain the concept of derived physical quantities with an example.
Derived quantities are defined by combinations of fundamental quantities, like speed (distance divided by time) or acceleration (change in velocity divided by time).
Differentiate between vector and scalar quantities.
Vector quantities have both magnitude and direction (e.g., velocity), while scalar quantities possess only magnitude (e.g., speed).
How are vector quantities represented in physics?
Vectors are typically represented by arrows, with length indicating magnitude and direction indicating the physical direction.
Provide examples of scalar quantities that are frequently encountered in everyday life.
Time, mass, temperature, and speed are common scalar quantities as they have magnitudes but no specific direction associated with them.
What is Buoyant force?
The net force acting on a body due to the difference between the upward and downward pressure
What is fluid pressure?
The pressure exerted by a fluid in an object inside the fluid
What was the Archimedes principle?
The buoyant force applied by the fluid is equal to the weight of the displaced fluid
What is density, what is the unit and what formula to calculate it
Amount of mass present per unit volume
P = Mass/Volume
Unit = kgms^-3
Fluid resistance
Fluid resistance is the force that a fluid exerts on a moving object in the opposite direction to the movement. It’s also known as drag
