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OpenStem
@openstem · Joined Jul 2026
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Flashcards11 cards
What is a trajectory?1 / 11
A trajectory is the curved path a thrown or launched object follows through the air — like the arc a basketball traces on its way to the hoop.
Physics · L2 · Projectile Motion Basics
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Physics · L2 · Projectile Motion BasicsFlashcards10 cards
What physical property of a vibration decides a sound's pitch?1 / 10
Frequency — how fast the source vibrates back and forth. A fast vibration makes a high pitch, a slow vibration makes a low pitch.
Physics · L2 · Sound: Pitch, Loudness & Echoes
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Physics · L2 · Sound: Pitch, Loudness & EchoesFlashcards10 cards
What is the center of mass of an object?1 / 10
The center of mass is the single point where all of an object's weight seems to act from — its overall balance point. Support that one point, and the whole object balances, even though its weight is actually spread out through it.
Physics · L2 · Center of Mass & Stability
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Physics · L2 · Center of Mass & StabilityFlashcards10 cards
What is a concave mirror?1 / 10
A mirror that curves inward, like the inside of a spoon or a satellite dish. It reflects light off a bowl-shaped surface instead of a flat one.
Physics · L2 · Curved Mirrors
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Physics · L2 · Curved MirrorsFlashcards9 cards
What is periodic motion?1 / 9
Periodic motion is any motion that repeats itself over and over in the same regular pattern — a swinging pendulum, a bouncing ball on a trampoline, a rocking chair, or the ticking pendulum inside a grandfather clock.
Physics · L2 · Pendulums & Periodic Motion
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Physics · L2 · Pendulums & Periodic MotionFlashcards8 cards
What does "mechanical advantage" mean?1 / 8
How many times a simple machine multiplies the force you put in. A mechanical advantage of 4 means the machine turns your push into a push four times as strong.
Physics · L2 · Mechanical Advantage: Levers & Pulleys
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Physics · L2 · Mechanical Advantage: Levers & PulleysFlashcards8 cards
What does this formula calculate?1 / 8
Electrical power — how fast a device uses energy — from the current (I) flowing through it and the voltage (V) across it.
Physics · L2 · Electrical Power & Energy
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Physics · L2 · Electrical Power & EnergyFlashcards8 cards
What generally happens to the size of most materials when they're heated?1 / 8
They expand — their particles vibrate more and spread slightly farther apart, so the material takes up more space.
Physics · L2 · Thermal Expansion
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Physics · L2 · Thermal ExpansionFlashcards8 cards
What is a magnetic field line meant to show?1 / 8
The direction a tiny compass needle would point at that spot, and how strong the magnetic pull is there — lines closer together mean a stronger field.
Physics · L2 · Magnetic Field Lines & Earth's Magnetism
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Physics · L2 · Magnetic Field Lines & Earth's MagnetismFlashcards8 cards
What is an echo?1 / 8
A sound wave that reflects off a surface — like a wall or cliff — and comes back to your ears a moment later.
Physics · L2 · Echoes, Sound Reflection & Sonar
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Physics · L2 · Echoes, Sound Reflection & SonarFlashcards8 cards
What does this equation, Hooke's Law, describe?1 / 8
The force needed to stretch or compress a spring, where k is the spring constant and x is how far it's stretched or compressed from its natural length.
Physics · L2 · Springs & Hooke's Law
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Physics · L2 · Springs & Hooke's LawFlashcards8 cards
What equation is Newton's Second Law written as?1 / 8
: net force equals mass times acceleration.
Physics · L3 · Newton's Second Law
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Physics · L3 · Newton's Second LawFlashcards7 cards
Two forces, 20 N and 15 N, push an object in the same direction. What is the net force?1 / 7
Forces in the same direction add together: 20 N + 15 N = 35 N in that direction.
Physics · L3 · Newton's Second Law
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Physics · L3 · Newton's Second LawFlashcards9 cards
An object moves in a circle at constant speed. Which way does its acceleration point?1 / 9
Toward the center of the circle. Even though the speed is constant, the direction keeps changing — and any change in velocity is an acceleration.
Physics · L3 · Circular Motion
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Physics · L3 · Circular MotionFlashcards10 cards
What does Newton's law of universal gravitation say?1 / 10
Every object with mass attracts every other object with mass. The pull is stronger for bigger masses and weaker the farther apart they are.
Physics · L3 · Universal Gravitation
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Physics · L3 · Universal GravitationFlashcards8 cards
What is the formula for the momentum of an object?1 / 8
Momentum
Physics · L3 · Conservation of Momentum
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Physics · L3 · Conservation of MomentumFlashcards8 cards
What defines an elastic collision?1 / 8
Both momentum AND total kinetic energy are conserved. The objects bounce apart rather than sticking, and no kinetic energy is converted to heat, sound, or deformation.
Physics · L3 · Conservation of Momentum
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Physics · L3 · Conservation of MomentumFlashcards8 cards
What does the work-energy theorem state?1 / 8
The net work done on an object equals its change in kinetic energy: W_net = ΔKE. If more work goes in than comes out, the object speeds up; if net work is negative, it slows down.
Physics · L3 · Work-Energy Theorem
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Physics · L3 · Work-Energy TheoremFlashcards7 cards
A 2 kg cart starts at rest and is pushed by a net force of 10 N over a distance of 4 m. What is its final speed?1 / 7
W_net = F·d = 10 × 4 = 40 J = ΔKE = ½(2)v_f² − 0, so v_f² = 40 and v_f ≈ 6.3 m/s.
Physics · L3 · Work-Energy Theorem: Practice Problems
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Physics · L3 · Work-Energy Theorem: Practice ProblemsFlashcards9 cards
What is the wavelength (λ) of a wave?1 / 9
The distance between two corresponding points on consecutive cycles of a wave — for example, crest to crest or trough to trough. Measured in metres.
Physics · L3 · Wave Properties
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Physics · L3 · Wave PropertiesFlashcards8 cards
What is a transverse wave?1 / 8
A wave in which particles of the medium move perpendicular (at right angles) to the direction the wave travels — like a rope flicked up and down while the wave moves sideways.
Physics · L3 · Wave Properties
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Physics · L3 · Wave PropertiesFlashcards11 cards
What is Ohm's Law?1 / 11
V = I × R — voltage equals current times resistance.
Physics · L3 · Resistor Circuits
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Physics · L3 · Resistor CircuitsFlashcards11 cards
State the law of reflection.1 / 11
The angle of incidence equals the angle of reflection, both measured from the normal — the line perpendicular to the surface at the point of contact. In symbols, θᵢ = θᵣ.
Physics · L3 · Reflection & Refraction
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Physics · L3 · Reflection & RefractionFlashcards7 cards
Light travels from air (n = 1.00) into glass (n = 1.50) at an incidence angle of 30°. Set up Snell's law for this.1 / 7
1.00 · sin(30°) = 1.50 · sinθ₂, so sinθ₂ = (1.00 × 0.50) / 1.50 = 0.333, giving θ₂ ≈ 19.5°.
Physics · L3 · Snell's Law Practice
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Physics · L3 · Snell's Law PracticeFlashcards10 cards
Why can projectile motion be analyzed as two separate 1D motions?1 / 10
Because horizontal and vertical motion are independent of each other. Gravity only acts vertically, so it never changes the horizontal velocity — and nothing pushes the object sideways, so nothing changes the vertical motion's timing. Treating them as two separate, simultaneous problems (constant velocity sideways, constant acceleration down) is what makes the curved path solvable with straight-line kinematics.
Physics · L3 · Projectile Motion
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Physics · L3 · Projectile MotionFlashcards9 cards
What is torque?1 / 9
A measure of how much a force makes an object rotate around a pivot point. It's the rotational equivalent of an ordinary push or pull — instead of causing straight-line acceleration, it causes angular acceleration.
Physics · L3 · Torque & Rotational Equilibrium
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Physics · L3 · Torque & Rotational EquilibriumFlashcards10 cards
What condition on the restoring force defines simple harmonic motion (SHM)?1 / 10
The restoring force must be proportional to the displacement from equilibrium, and always point back toward it. A spring obeying Hooke's law does this exactly; a pendulum does it approximately, for small swing angles.
Physics · L3 · Simple Harmonic Motion: Springs & Pendulums
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Physics · L3 · Simple Harmonic Motion: Springs & PendulumsFlashcards10 cards
What is Coulomb's law?1 / 10
k ≈ 8.99 × 10⁹ N·m²/C² is Coulomb's constant, q₁ and q₂ are the two charges in coulombs, and r is the distance between them.
Physics · L3 · Electric Fields & Coulomb's Law
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Physics · L3 · Electric Fields & Coulomb's LawFlashcards10 cards
A charged particle sits still inside a strong magnetic field. What magnetic force does it feel?1 / 10
Zero. A magnetic field exerts no force at all on a charge that isn't moving — that's a key difference from the electric force, which pushes on a charge whether it's moving or standing still.
Physics · L3 · Magnetic Force on Moving Charges
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Physics · L3 · Magnetic Force on Moving ChargesFlashcards10 cards
What is the specific heat formula, and what does each symbol mean?1 / 10
q is heat energy in joules, m is mass in kg, c is the substance's specific heat capacity in J/(kg·°C), and ΔT is the temperature change in °C.
Physics · L3 · Specific Heat & Calorimetry
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Physics · L3 · Specific Heat & Calorimetry