Measurement and Scalars vs Vectors

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Questions and Answers

What is the main difference between speed and velocity?

Speed is the rate of change of distance, while velocity is the rate of change of displacement. (correct)

Speed is greater than velocity in all cases.

Speed has magnitude and direction, while velocity only has magnitude.

Speed is a vector quantity, while velocity is a scalar quantity.

How is acceleration defined in kinematics?

The rate of change of speed.

The rate of change of displacement.

The rate of change of distance.

The rate of change of velocity. (correct)

What does the gradient of a displacement-time graph represent?

Acceleration of the body.

Change in velocity of the body.

Velocity of the body. (correct)

Distance travelled by the body.

In addressing uncertainty associated with a quantity raised to the nth power, what formula should be used?

Δz/z = |n| × (Δx/x) Signup and view all the answers

What information can be derived from the area under a velocity-time graph?

Change in displacement of the body. Signup and view all the answers

What does the number of electric field lines per unit cross-sectional area represent?

The strength of the electric field Signup and view all the answers

Which factor does NOT influence the strength of a magnetic field in a solenoid?

The voltage supplied to the solenoid Signup and view all the answers

In the equation F = BIl sinθ, what does the symbol F represent?

Force experienced by the conductor Signup and view all the answers

What does Fleming’s left-hand rule determine in the context of magnetic fields?

The direction of force on a conductor Signup and view all the answers

Which statement is true about magnetic flux density B?

It is the magnetic force per unit length on a current-carrying conductor Signup and view all the answers

What is the primary characteristic of geostationary satellites?

They orbit Earth at a fixed position relative to the surface. Signup and view all the answers

Which equation relates the current to the rate of flow of electric charge?

$Q = It$ Signup and view all the answers

What must be true for a satellite to be classified as geostationary?

Its orbital plane must align with the equator. Signup and view all the answers

Which equation can be used to find the resistance of a circuit component?

$V = IR$ Signup and view all the answers

What is the significance of geostationary satellites for communication systems?

They allow fixed antennas on Earth to stay aligned with the satellite. Signup and view all the answers

What is the weight of a body?

The gravitational force experienced by a mass in a gravitational field Signup and view all the answers

What does the principle of conservation of momentum state?

Total momentum remains constant unless acted upon by an external force Signup and view all the answers

In a perfectly elastic collision, which of the following is true?

Momentum is conserved and kinetic energy is also conserved Signup and view all the answers

If two bodies collide inelastically, what happens to their kinetic energy?

Some kinetic energy gets converted to other forms of energy Signup and view all the answers

What is the formula for linear momentum?

Momentum = mass x velocity Signup and view all the answers

What is impulse defined as?

The product of force and time of impact Signup and view all the answers

What characterizes a completely inelastic collision?

Kinetic energy is minimized and bodies stick together Signup and view all the answers

What is the relationship between resultant force and momentum?

Resultant force equals the rate of change of momentum Signup and view all the answers

What is the formula used to calculate the magnetic flux density in a current balance?

B = mgd2 / Ild1 Signup and view all the answers

Which direction does Fleming's left-hand rule indicate the force acts when currents flow in the same direction?

Attraction between conductors Signup and view all the answers

When using Fleming's left-hand rule, which finger represents the direction of the magnetic field?

Index finger Signup and view all the answers

What occurs when two current-carrying conductors have currents flowing in opposite directions?

They repel each other Signup and view all the answers

In the equation F = BQv sinθ, what does the variable 'v' represent?

Velocity of the charge Signup and view all the answers

What is the relationship between the force experienced by an electrically charged particle and the electric field strength?

F = qE Signup and view all the answers

What condition must be met for a current-carrying coil to achieve rotational equilibrium in a magnetic field?

The pivot positions must create equal moments about the pivot. Signup and view all the answers

How does the direction of force on a moving charge in a magnetic field change with the charge's movement?

It is opposite to the direction of movement for negative charges. Signup and view all the answers

What does the equation Ep = mgh represent in physics?

Gravitational potential energy changes near the Earth's surface Signup and view all the answers

According to Newton’s Second Law, what is the force exerted when a body of mass m is lifted without changing its velocity?

F = mg Signup and view all the answers

What is the instantaneous power when a constant force F acts on an object moving with velocity v?

P = Fv Signup and view all the answers

What unit of measurement is used for angular displacement?

Radians Signup and view all the answers

How is angular velocity (ω) related to the frequency (f) of rotation?

ω = 2πf Signup and view all the answers

Which equation relates linear velocity (v) to angular velocity (ω) in circular motion?

v = rω Signup and view all the answers

What is the formula for calculating power (P) based on work done (W) over time (t)?

P = W / t Signup and view all the answers

In uniform circular motion, which of the following statements is true regarding angular velocity?

Angular velocity is constant at all points on a rotating body Signup and view all the answers

Study Notes

Topic: Measurement

Physical quantities and SI units
- Base quantities: mass (kilogram), length (meter), time (second), current (ampere), temperature (kelvin), amount of substance (mole)
- One mole of any substance contains 6.02 x 10²³ particles (Avogadro's number)
- Derived units are expressed as a combination (products or quotients) of base units.
- A physical equation is homogeneous if all terms have the same units.
- Quantities added/subtracted must have the same units.
- Equations that are valid must be homogeneous.
- Graph axes and table headings should include quantities and corresponding units (e.g., L/m).
- Numerical labels on axes should have the same number of decimal places.
- Prefixes and symbols (e.g., pico (p) - 10^-12, nano (n) - 10^-9, micro (μ) - 10^-6, milli (m) - 10^-3, etc.) for sub-multiples and multiples.

Topic: Scalars and Vectors

Distinction between scalar and vector quantities.
- Scalars have magnitude only (e.g., mass, time, length, volume, temperature, density, speed, energy, pressure, current).
- Vectors have both magnitude and direction (e.g., displacement, velocity, acceleration, force, momentum).
Addition and subtraction of coplanar vectors:
- Parallel vectors: simple addition/subtraction.
- Non-parallel vectors: parallelogram or triangle of vectors.
- Representation using components: horizontal and vertical components resolved.

Topic: Errors and Uncertainties

Distinction between systematic and random errors:
- Systematic errors have a constant magnitude (always positive or negative), e.g., zero error.
- Random errors have varying magnitudes (equal chance of being positive or negative).
Distinction between precision and accuracy:
- Precision: closeness of individual measurements to each other.
- Accuracy: closeness of a measured value to the true value.
Assessing uncertainty in a derived quantity:
- Addition/subtraction: add absolute uncertainties.
- Multiplication/division: add fractional/percentage uncertainties.
- Constant multiplication: multiply absolute uncertainty by the constant.

Topic: Rectilinear Motion

Displacement, speed, velocity, and acceleration: Their definitions and representations.
Graphical representations: distance-time, displacement-time, speed-time, velocity-time, and acceleration-time graphs.
Derivation of equations of uniformly accelerated motion (e.g., v = u + at, s = ut + 0.5at², v² = u² + 2as).
Solving problems using these equations.
Uniformly accelerated motion in a straight line, deriving relationships and solving problems, sketching diagrams, etc.

Topic: Dynamics

Newton's laws of motion: 1st law (inertia), 2nd law (F=ma), 3rd law (action-reaction).
Applying Newton's laws to solve problems involving forces and motion.
Mass as the property resisting change in motion (inertia).
Concept of weight.

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Description

This quiz covers fundamental concepts of measurement, including physical quantities, SI units, and the distinction between scalars and vectors. Explore base units, derived units, and the importance of homogeneous equations in physical contexts. Test your knowledge on the prefixes and symbols used in measurements.