unit 1 - kinematics Flashcards
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 Instantaneous speed
Distance travelled by a body in a very short interval of time
How does a distance-time graph depict an object’s speed
by the object’s slope
What is terminal Velocity/Speed
A constant velocity with which a body falls down under the influence of gravitational force and fluid resistance
If there is no applied force acting on a body, the frictional force will be
ZERO
Frictional force will continue to increase with increase in
applied force
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.
Value of frictional force =
Value of applied force
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?
Force developed within any material which is elastic in nature and 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 static friction?
Friction that acts on objects that are at rest. Increases with applied force and has a max possible vlaue
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 friction
Why does the statsic friction drop after reaching limiting friction when force is applied?
Because the objects starts moving and kinetic friction takes over
What is the max possible value of static friction called?
Limiting Friction, when the applied force exceeds this value, the body starts to move.
What is momentum. Unit and type of quantity
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 acceleration of a body is directly proportional to the force applied and indirectly proportional to its mass
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
What is a force
Described as a push and pull on an object interacting with another object
Effect of force on an object
- Start or end motion
- Change an object’s shape/size
What happens when an object is balanced in terms of moments
The Anticlockwise moment is equalt o the clockwise moment arounda a common pivot
Define moments/torque in physics
The rotational turning effect caused by a force on a body on its axis on a pivot point
What is a pivot
the point at which the lever is supported and around which it rotates
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 Impulse
Change in momentum
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)
P = F/A
Pressure and area are what type of relationship
inversely related (pressure increases, area decreases)
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 is Inelastic collisions?
Kinetic energy is not conserved and is transformed into other forms of energy after the collision. Both objects move in same direction
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
Work definition and formula
Work is said to be done is a force displaces an object in the direction of the force applied.
W = Force * displacement
W = Force * displacement * cos θ
Power defination and formula
Rate at which work is done
P = Work done/time
P = (Force * displacement)/time
P = force * velocity
Equation of best fit line formula for desmos
y1 ~ mx1 + b
Weight
force exerted on an object due to its gravity
Mass can never change, but weight can change
W = mg
Escape velocity
Minimum velocity required to escape a planet’s gravitational field
Spring constant
its a measure of how stiff or rigid a spring is. It tells us how much force is needed to stretch or compress a spring by a certain distance.
A higher value would mean a more sitffer string and a lower value would mean a loose string
Work-energy theorem
Work done can be represented as change in KE
