Free HSC Physics Flashcard Review

Motion of an object under the influence of gravity alone, with constant vertical acceleration (g = 9.8 m/s²) and zero horizontal acceleration (assuming no air resistance).

x = v₀cosθ × t, where v₀ is initial velocity, θ is angle of projection, and t is time. Horizontal velocity remains constant throughout flight.

y = v₀sinθ × t − ½gt², where v₀sinθ is initial vertical velocity. Vertical motion follows constant acceleration equations with a = −g.

Motion of an object moving at constant speed along a circular path. The velocity direction continuously changes, requiring constant acceleration directed toward the centre.

a_c = v²/r = ω²r, where v is tangential speed, r is radius, and ω is angular velocity. Direction is always toward the centre of the circle.

F_c = ma_c = mv²/r = mω²r, where m is mass. This is the net force directed toward the centre required to maintain circular motion.

The rate of change of angular displacement with respect to time. Symbol ω, measured in rad/s. Related to period T by ω = 2π/T.

T² ∝ r³, or T²/r³ = constant = 4π²/GM. The square of the orbital period is proportional to the cube of the orbital radius for objects orbiting the same central body.

E_p = −GMm/r, where G is the gravitational constant, M is the mass of the central body, m is the mass of the object, and r is the distance from the centre. Zero potential energy is defined at infinity; values are negative.

The minimum velocity required for an object to escape the gravitational field of a body entirely, reaching infinite distance with zero kinetic energy. Derived from E_k + E_p = 0 at escape.

v_e = √(2GM/r), where G is gravitational constant, M is the mass of the body, and r is the distance from the centre. Independent of the object's mass.

F = kQ₁Q₂/r², where F is the force between two charges, k = 8.99 × 10⁹ N m²/C², Q₁ and Q₂ are the charges, and r is the distance between them. Force is repulsive for like charges, attractive for unlike charges.

The electric force per unit positive charge: E = F/q = kQ/r². Units: N/C or V/m. Direction is the direction of force on a positive test charge.

F = BIL sinθ, where B is magnetic flux density, I is current, L is length of conductor in the field, and θ is the angle between the conductor and field. Direction determined by the right-hand rule (force, current, field).

A current-carrying conductor in a magnetic field experiences a force perpendicular to both the current and field. This effect is the basis for electric motors, where the force on coils causes rotation.

τ = nBIA sinθ, where n is the number of turns, B is magnetic flux density, I is current, A is the area of the coil, and θ is the angle between the normal to the coil and the field. Units: N m.

The magnitude of induced EMF is directly proportional to the rate of change of magnetic flux: ε = −N(ΔΦ/Δt), where N is the number of turns and Φ = BA cosθ is magnetic flux.

The direction of an induced EMF (or current) is such that it opposes the change in magnetic flux that produced it. Gives the negative sign in Faraday's law: ε = −N(ΔΦ/Δt).

Φ = BA cosθ, where B is magnetic flux density, A is the area perpendicular to the field, and θ is the angle between the field and the normal to the area. Units: Wb (Weber) or T m².

V_p/V_s = N_p/N_s = I_s/I_p, where subscripts p and s denote primary and secondary. Power is conserved (ignoring losses): V_pI_p = V_sI_s.