Physics Fundamentals

1 Motion, forces and energy

1.1 Physical quantities and measurement techniques

• Lengths are measured using tapes, rulers and micrometers.
• The measuring cylinder helps measure a liquid's volume and determine the volume of a solid using the displacement method.
• The time duration can be measured using clocks and digital timers.
• An average value for a small distance, and a short interval of time is determined by measuring multiples.
• A scalar quantity is magnitude without specified direction.
• A vector quantity is magnitude and direction.
• Distance, speed, time, mass, energy, and temperature are scalar quantities.
• Displacement, force, weight, velocity, acceleration, momentum, electric field strength, and gravitational field strength are vector quantites.
• The resultant of two vectors at right angles can be determined by calculation or graphically.

The metre rule and measuring tape

• A metre rule can measure lengths up to one metre.
• A steel measuring tape is suitable for measuring straight distances longer than a metre.
• A cloth measuring tape is suitable for measuring the length along a curved surface, such as a person's waist.

What is the precision of an instrument?

• The metre ruler has a precision of 1 mm.

How to determine an average value for a small distance?

• The thickness of a sheet of paper is less than the precision of a metre rule (i.e. 1 mm).
• The average thickness of a sheet of paper is done by measuring the thickness of several sheets of paper together and dividing by the number of sheets.

How do we avoid errors in measurement?

• The eyes should be positioned so the line of sight is perpendicular to the rule to avoid parallax error.

Micrometer:

• The precision of the micrometer is 0.01 mm.
• An analogue micrometer requires reading the scale.

Volume of liquids

• The volume of a liquid is found by pouring the liquid into a measuring cylinder and reading the volume.
• The measuring cylinder will rest on a flat horizontal surface with no liquid bubbles.

Volume of irregular solids

• The volume of a small object is determined using V = V2 - V1, where V1 = volume of water before putting in the object and V2 = volume reading after putting in the object.

How do we find the volume of large objects that sink?

• A displacement can and a measuring cylinder finds the volume of large objects that sink.
• A sinker helps measure the volume of floating objects.

Clocks and stopwatches

• Clocks and watches use quartz crystals.
• Most stopwatches can measure time to a precision of 0.01 s.
• Human reaction time is about 0.3–0.5 s for most people.

Determine an average value for a short interval of time by measuring multiples

• The path of one complete oscillation goes from X to Y and back to X or from Y to X and back to Y.

Scalar quantity:

• A scalar quantity has magnitude (size) only.
• Examples of scalar quantities are distance, speed, time, mass, energy and temperature.

Vector quantity

• A vector quantity has magnitude and direction.
• Examples: displacement, force, weight, velocity, acceleration, momentum, electric field strength and gravitational field strength

Determine, by calculation or graphically, the resultant of two vectors at right angles:

• The direction is positive towards the right.
• Resultant vector is usually indicated by a double-headed arrow.

Adding non-parallel vectors

• Forces are added to obtain a resultant force.
• The resultant force R can be obtained graphically by drawing a parallelogram and is the parallelogram's diagonal.
• The Pythagorean theorem R = √(F1² + F2²) determines the resultant foorce R by calculation.

Graphical method:

• Calculate the resultant of two forces of 3.0N and 4.0 N
• The values for F and θ can be drawing vectors.

1.2 Motion

• Speed is distance travelled per unit time and velocity is change in displacement per unit time.
• Speed = distance/time
  • v=s/t
• Average Rate of change of distance is total distance travelled/total time taken.
• Acceleration is change in velocity per unit time
  • Acceleration = change in velocity/time taken
    • a = Δv/Δt
• Uniform acceleration is constant acceleration, non-uniform acceleration is changing acceleration.
• Deceleration is a negative acceleration.
• Distance-time and speed-time graphs, showing slopes
  • Determine graphs when an object is at rest, moving with constant speed, accelerating, etc.
• The acceleration of free fall g for an object near to the surface of the Earth is approximately constant and is approximately 9.8 m/s².
  • Calculate speed from the gradient of a distance-time graph
  • Calculate the area under a speed-time graph to determine the distance travelled for motion with constant speed or constant acceleration.
  • Calculate acceleration from the gradient of a speed-time graph.

Distance:

• The length along the actual path travelled from the starting point to the finishing point is the distance moved by a particle.
• Distance is a scalar quantity.
• The unit of distance is cm, m

Displacement:

• A particle's change of position is displacement.
• The displacement measures the length travelled in a specified direction from the starting point to the finishing point.
• Displacement is a vector quantity
• Units are cm, m.

Speed:

• Speed measures distance travelled per unit time.
• Speed = distance travelled/time taken
  • v = s/t
• Meters per second (m/s) is the unit of speed.
• Average speed =total distance travelled total time taken

Velocity:

• Velocity describes the change in displacement per unit time.
  • Velocity = change in displacement / total time taken
• Unit: m/s

Acceleration:

• Acceleration measures the change of velocity per unit time.
• Its commonly used unit is meter per second per second (m/s²).
• Acceleration = change of velocity time
  • a = v-u/t = ∆v/At where v represents final velocity, u represents initial velocity, and t represents total time taken
• Example 1.
  • V =5 is displacement changes uniformly. So constant acceleration, uniform acceleration, and no acceleration is no change in velocity
• Example 2.
  • Uniform acceleration means change in velocity per unit time is constant
• Example 3.
  • Non-uniform acceleration means change in velocity per unit time is not constant, with increased acceleration.
• Example 4.
  • Decreasing acceleration, means more uniform acceleration is not more constant
  • Note: it is not deceleration
• Example 5 Speed time graph:
  • Velocity decreases means
  • De deceleration
  • Is a Negative acceleration. –Uniformly change

Distance–time graphs: Gradient of the graph = speed

• Characteristics:
  • Gradient = 0, so speed = 0
    • Static and acceleration =0
    • Gradient constant, and it increases and moving with constant speed acceleration is0
    • Increasing gradient, are increasing speed the Object is accelerating
    • Decreasing gradient So decreasing the speed of is the Object is de accelerating
• In speed time graph the are of its is Acceleration

Speed–time graphs: are as follows

-. The relationship between gradient of the graph = are deceleration

• And Area under the graph ==distance for Travelling
• Velocity increase uniformly - And constant acceleration = 0 - Travelling equal with are the area of the triangle - The velocity is constant, so acceleration 0,

1.3 Mass and weight

• It is the Mass is a measure of the quantity of matter in an object at rest relative to the observer

• It objects change is Mass as responsible for acceleration or an inertia.

• It’s is also known to have More mass, more inertia Units: g, kg

• A gravitational field is region in which a mass experiences a reaction -is Weight is the gravitational force experienced by the object.,Units: N

  • Also with the assistance of gravitational strength = weight / mass.

Differences between mass and weight: are as follows.

• The Amount of matter for Mass is scalar

The	gravity is gravitational force is vector and the units units has used kilogram with the beam calibration and balance it.

• It’s in the weight as string with Spring and the mass is with scale

1.4 Density. A volume parameter with its mass per units volume, the equation is,

density =MASS / VOLUME.

• For example, The volume is m3

1.5 Density

It’s an describe mass per units volume with recall the equipment. density = mass / volume

1.5 FORCED And Balances And Un Balances OF The Forces.

• The different type of force include weight( gravitational force), friction, direct resistance, tension elastic forest, electric, forest, electric thrust driving fork and contact force
• Identify with forces and free, bodily diagram, represent the in forces
  • State that Newton’s 1st law as an objects, EITHER remains more at resting are Continues to move in for a straight line at constant speed unless acted in for a resistant force. - State that for FORCE may change the velocity of the object change it’s that are direction of the motion were Speed, and in a the in to resultant were as it the forces act act and to the. SAME straight lin • The recall with usage the equation : Resultant Force
  • = are mass acceleration Force = MA.

State Newton’s 3RD law as object object a exertion Force on. Object B. B exert equal with apposite fork and to the

• Know with describe of same
• A gravitational forces, it’s a force that Impeding motion
• it