Kit Library / Science / Physics
⚡ Topic Learning KitShared by a Veda learner · Generated with Veda AI
Veda Bites are swipeable micro-lessons — each one teaches exactly one idea. The bites below come from this kit — swipe through them in the app.
Everything that moves obeys these 3 rules.
Newton's three laws form a complete framework for understanding force and motion in everyday life.
↳ Master these three laws and you can predict how any object responds to forces.
Objects are lazy — they resist change.
↳ No net force means no change in motion — inertia is why you lurch forward when a bus brakes.
The equation that links force, mass, and acceleration.
↳ Force and acceleration are directly proportional; mass is the resistance to acceleration.
Push something — it pushes back equally.
The forces do not cancel because they act on different objects.
↳ Forces always come in pairs — but each force acts on a different object, so they never cancel out.
They're equal — so why does anything move?
↳ Cancellation requires forces on the same body — action–reaction pairs act on two different bodies.
Your body keeps moving even when the bus stops.
↳ Seatbelts exist because of inertia — they provide the force needed to stop your body with the car.
Rockets push gas down to go up.
A rocket expels hot gas downward at high speed. By Newton's Third Law, the gas pushes the rocket upward with an equal and opposite force.
↳ Rockets don't push against air — they push against their own exhaust, and the exhaust pushes back.
Plug in force and mass — get acceleration.
↳ Rearrange F = ma to a = F/m whenever you need acceleration from force and mass.
Mass is matter; weight is force.
↳ Mass is intrinsic and constant; weight depends on the local gravitational field.
Your weight is just gravity pulling on your mass.
A 60 kg student weighs about $60 \times 9.8 = 588$ N on Earth — but only about 98 N on the Moon.
↳ Weight is the force of gravity on a mass — it changes with g, but mass does not.
Three letters, three laws.
↳ I-F-R: Inertia, Force, Reaction — in that order.
One diagram saves ten mistakes.
↳ Free-body diagrams turn messy force problems into clean equations — examiners award method marks for them.
These laws need a stable viewpoint.
Newton's laws are valid only in inertial (non-accelerating) reference frames. In an accelerating frame, you must add pseudo-forces (like centrifugal force) to make the laws work.
↳ Newton's laws assume an inertial frame — accelerating frames require fictitious forces.
Over 300 years old — still used daily.
Isaac Newton published his three laws in *Philosophiæ Naturalis Principia Mathematica* in 1687. They remain the backbone of classical mechanics and are still used to send spacecraft to other planets.
↳ Newton's 1687 Principia introduced the three laws that still power modern engineering.
Wrong units = wrong answer.
↳ Dimensional analysis catches most algebra slips before they cost you marks.
Newton's three laws of motion describe how forces affect the motion of objects: objects resist changes in motion (inertia), force causes acceleration proportional to mass, and every action has an equal and opposite react…
Full explanation, worked examples & memory tricks in the app
All 17 questions, laddered from warm-up to topper-level, each with its answer and the reasoning behind it.
Q1. Which statement best describes Newton's first law of motion?
BeginnerA · An object stays at rest or in uniform motion unless a net external force acts.
The first law (law of inertia) states that without a net external force, an object maintains its state of rest or uniform motion.
Q2. A hockey puck slides across frictionless ice at constant velocity. What is the net force on the puck?
BeginnerB · Zero, because its velocity is constant.
Constant velocity means zero acceleration, so by the second law the net force is zero. No forward force is needed to keep it moving.
Q3. Which quantity is a measure of an object's inertia?
BeginnerC · Its mass
Inertia depends on mass: a more massive object resists changes in motion more strongly.
Q4. The SI unit of force, the newton, is equivalent to which combination of units?
BeginnerA · $\text{kg}\cdot\text{m/s}^2$
From $F = ma$, one newton is the force giving a $1\,\text{kg}$ mass an acceleration of $1\,\text{m/s}^2$, so $1\,\text{N} = 1\,\text{kg}\cdot\text{m/s}^2$.
Q5. Newton's second law is expressed as $\vec{F}_{net} = m\vec{a}$, where force and acceleration are vectors.
BeginnerA · True
Newton's second law is expressed as $\vec{F}_{net} = m\vec{a}$, where force and acceleration are vectors.
Q6. A $4\,\text{kg}$ object experiences a net force of $12\,\text{N}$. What is its acceleration?
IntermediateB · $3\,\text{m/s}^2$
Using $a = F_{net}/m = 12/4 = 3\,\text{m/s}^2$.
Q7. A box is pushed right with $20\,\text{N}$ while friction of $5\,\text{N}$ acts left. What is the net force?
IntermediateB · $15\,\text{N}$ to the right
Net force is the vector sum: $20 - 5 = 15\,\text{N}$ to the right. Friction must be included.
Q8. Two identical carts are pushed with the same net force. Cart A is empty; Cart B carries a heavy load. Which accelerates more?
IntermediateB · Cart A, because it has less mass.
For the same net force, acceleration is inversely proportional to mass, so the lighter cart A accelerates more.
Q9. A swimmer pushes water backward. Why does the swimmer move forward?
IntermediateD · The water pushes the swimmer forward with an equal and opposite force.
This is Newton's third law: the swimmer's backward push on the water is matched by a forward push of the water on the swimmer.
Q10. Why don't the action and reaction forces in Newton's third law cancel each other?
IntermediateD · They act on different objects, so each object feels only one of them.
Cancellation requires forces on the same object. Action and reaction act on different bodies, so each body accelerates according to the single force it feels.
Q11. A car suddenly brakes. A passenger lurches forward. Which law best explains this?
IntermediateB · The first law, because the passenger's inertia keeps them moving forward.
The passenger's body tends to keep its forward motion (inertia) when the car decelerates — a first-law effect, which is why seatbelts are needed.
Q12. A $2\,\text{kg}$ object accelerates at $5\,\text{m/s}^2$. What net force acts on it?
IntermediateC · $10\,\text{N}$
Using $F_{net} = ma = 2 \times 5 = 10\,\text{N}$.
Q13. A book rests on a table. The table pushes up on the book with a normal force. Which force is the third-law partner of this normal force?
AdvancedB · The book pushing down on the table.
Third-law pairs act on different objects and are the same type of force. The normal force from the table on the book pairs with the book's push on the table, not with gravity.
Q14. A rocket fires its engine in deep space, far from any planet. Which statement is correct?
AdvancedB · The rocket accelerates because the expelled gas pushes back on it.
The third law does not require an external medium: the rocket pushes gas one way, and the gas pushes the rocket the other way.
Q15. A $10\,\text{kg}$ crate is pulled right with $50\,\text{N}$ while friction of $20\,\text{N}$ acts left. What is its acceleration?
AdvancedA · $3\,\text{m/s}^2$ to the right
Net force is $50 - 20 = 30\,\text{N}$ to the right, so $a = 30/10 = 3\,\text{m/s}^2$ to the right. Using the applied force alone would be a mistake.
Q16. Two students disagree. Student A says: 'If action and reaction are equal and opposite, a horse can never pull a cart.' Student B says: 'The horse can pull the cart because the forces act on different objects.' Who is right, and why?
AdvancedA · Student B: the cart feels the horse's pull, while the horse feels the cart's pull, so the cart accelerates.
Third-law pairs act on different objects. The cart responds only to the horse's pull on it, so it can accelerate. The forces are equal in magnitude but never cancel because they are on different bodies.
Q17. A $10\, ext{kg}$ cart is subjected to two forces: a $40\, ext{N}$ force to the right and a $15\, ext{N}$ force to the left. Calculate the acceleration of the cart.
AdvancedA · 2.5 m/s² to the left
To find the acceleration, first calculate the net force: $F_{net} = 40\, ext{N} - 15\, ext{N} = 25\, ext{N}$ to the right. Then, use the second law: $a = \frac{F_{net}}{m} = \frac{25\, ext{N}}{10\, ext{kg}} = 2.5\, ext{m/s}^2$ to the right. However, since the left force is greate…
18 flashcards in this kit — the app reviews them with spaced repetition so the right card returns on the right day.
Every game is built from this kit's own content — scores feed your mastery, so playing counts as studying.
Word Match
Built from this kit's own content
True False
Built from this kit's own content
Memory Match
Built from this kit's own content
Flashcard Battle
Built from this kit's own content
Speed Quiz
Built from this kit's own content
Guess Term
Built from this kit's own content
Sequence Builder
Built from this kit's own content
Categorization
Built from this kit's own content
Revision Battle
Built from this kit's own content
Playable in the app
The full Veda Bites deck, complete notes, spaced-repetition flashcards, leveled MCQs, tests and games for this kit — plus Daily Facts and the Arena, every day.