Force
📚 Topic Overview: Basics of Force – Definition, Net Force & Effects
This section explains the basic ideas of force: push and pull, how forces act together
(net force), and how they change the motion, speed, shape, and direction of objects.
Questions from these ideas are common in school science and competitive exams because
they link directly to everyday experiences like walking, driving, playing games, and using tools.
1. Force – Push or Pull & Exploring Forces
Concept / Theory
A force is a push or a pull on an object. It arises
when two objects interact. We cannot see force itself, but we can see its effects.
Forces can be applied by muscles (muscular force), by machines, by gravity, by magnets,
by air, water, and many other sources.
Exploring Forces in Daily Life
- Pushing a school bench, pulling a chair, kicking a football.
- Lifting a bucket of water, dragging a suitcase, pressing a cycle brake.
- Earth pulling all objects downwards (gravitational force).
Basic Force Description Table
| Action | Type of Push / Pull | Object Affects |
|---|---|---|
| Pushing a cart | Push | Cart moves forward |
| Pulling a rope | Pull | Rope & attached load move |
| Kick a ball | Push (muscular) | Ball starts moving |
🧠 Keywords:
| English | Telugu |
|---|---|
| Force | బలం |
| Push | తొక్కడం |
| Pull | లాగడం |
🔍 Example / Real-Life Application:
In a local market, a vendor pushes a handcart full of vegetables. When he pushes harder,
the cart moves faster. When he stops applying force, the cart slowly stops due to friction.
This simple scene shows how push (force) starts and changes motion.
In a local market, a vendor pushes a handcart full of vegetables. When he pushes harder,
the cart moves faster. When he stops applying force, the cart slowly stops due to friction.
This simple scene shows how push (force) starts and changes motion.
📝 Exam Tip:
Remember the simplest idea: “Force = push or pull caused by interaction.”
Many questions just test if you can identify which actions involve a force and in which direction it acts.
Remember the simplest idea: “Force = push or pull caused by interaction.”
Many questions just test if you can identify which actions involve a force and in which direction it acts.
2. Net Force – Balanced & Unbalanced Forces
Concept / Theory
An object can have more than one force acting on it at the same time.
The net force is the overall (resultant) force obtained by
combining all forces (with direction) acting on the object.
When forces are equal in size and opposite in direction, they cancel each other
and are called balanced forces. When they do not cancel,
they are unbalanced forces and can change the state of motion.
Balanced vs Unbalanced Forces
| Type | Description | Effect on Motion |
|---|---|---|
| Balanced forces | Equal in size, opposite in direction | No change in speed or direction; object may stay at rest or move with uniform speed |
| Unbalanced forces | Not equal; one side is stronger | Change in state of rest or motion, speed or direction |
Simple Net Force Examples (One-Dimensional)
| Situation | Forces | Net Force | Result |
|---|---|---|---|
| Tug of war: both teams pull with equal strength | Left = 500 N, Right = 500 N | 0 N (balanced) | Rope does not move |
| Tug of war: left pulls 600 N, right pulls 500 N | Left = 600 N, Right = 500 N | 100 N to left (unbalanced) | Rope moves towards left team |
🧠 Keywords:
| English | Telugu |
|---|---|
| Net force | మొత్తం బలం |
| Balanced forces | సమతుల్య బలాలు |
| Unbalanced forces | అసమతుల్య బలాలు |
🔍 Example / Real-Life Application:
In a village sports day, children play tug of war. When both teams pull with equal effort,
the rope stays in the middle (balanced forces). When one team becomes stronger, the rope
moves towards that team (unbalanced forces). This shows net force deciding motion.
In a village sports day, children play tug of war. When both teams pull with equal effort,
the rope stays in the middle (balanced forces). When one team becomes stronger, the rope
moves towards that team (unbalanced forces). This shows net force deciding motion.
📝 Exam Tip:
Whenever a question says “object remains at rest” or “moves with constant speed in a straight line”,
think of balanced forces. If there is acceleration or change of direction,
there must be unbalanced force.
Whenever a question says “object remains at rest” or “moves with constant speed in a straight line”,
think of balanced forces. If there is acceleration or change of direction,
there must be unbalanced force.
3. Effects of Force – Motion, Speed, Direction & Shape
Concept / Theory
Force can bring about different types of changes in an object. The main
effects of a force are:
- Change the state of motion (start, stop, or change speed).
- Change the direction of motion.
- Change the shape or size of an object.
Change in State of Motion & Speed
- A stationary football starts moving when kicked.
- A moving cycle stops when brakes apply frictional force.
- A bus speeds up when the driver presses the accelerator (more force from engine).
Change in Direction
- In cricket, a bowler swings the ball; direction changes due to force from air and spin.
- Turning a vehicle at a curve involves force from tyres on the road, changing direction.
Change in Shape
- Pressing a rubber ball or sponge changes its shape temporarily.
- Hammering iron in a workshop changes its shape permanently.
🧠 Keywords:
| English | Telugu |
|---|---|
| Motion | చలనం |
| Speed | వేగం |
| Direction | దిశ |
🔍 Example / Real-Life Application:
In a busy town road, a bus starts from a bus stop (force from engine starts motion),
slows down near a speed breaker (opposing force from brakes and friction), turns at a junction
(change in direction), and finally stops at the next stop. All these changes are due to different
forces acting on the bus.
In a busy town road, a bus starts from a bus stop (force from engine starts motion),
slows down near a speed breaker (opposing force from brakes and friction), turns at a junction
(change in direction), and finally stops at the next stop. All these changes are due to different
forces acting on the bus.
📝 Exam Tip:
If a question asks “Which effect of force is shown here?”, check whether the change is in:
shape, speed, state of rest/motion, or direction.
Many questions are simple identification based on these four effects.
If a question asks “Which effect of force is shown here?”, check whether the change is in:
shape, speed, state of rest/motion, or direction.
Many questions are simple identification based on these four effects.
4. Exam Tips, Concept Highlights & Memory Sheet
Concept Highlights
- Force is always an interaction between at least two objects.
- Force has both magnitude (how strong) and direction (which way).
- Net force decides whether motion changes or not.
- Balanced forces → no change in motion (could be rest or uniform motion).
- Unbalanced forces → change in motion, speed, or direction.
- One force can cause more than one effect at the same time.
Quick Memory Sheet
| Idea | Short Memory Line |
|---|---|
| Definition of force | Force = push or pull due to interaction |
| Balanced forces | Equal and opposite, no net change in motion |
| Unbalanced forces | Unequal, cause acceleration or change in direction |
| Effects of force | Can change motion, speed, direction, shape |
Sample Question Ideas (for Practice Sets)
- Give two examples where force changes the shape of an object.
- Explain with an example what is meant by balanced forces.
- How can the same force change both speed and direction of a moving object?
- In a tug of war, what decides which team will win?
- Identify the type of effect in: (a) kicking a ball, (b) squeezing a sponge, (c) turning a bicycle.
📝 Strategy Tip:
For questions on forces, first ask:
“Is something starting, stopping, speeding up, slowing down, turning, or changing shape?”
This will usually tell you what kind of effect of force the question is testing.
For questions on forces, first ask:
“Is something starting, stopping, speeding up, slowing down, turning, or changing shape?”
This will usually tell you what kind of effect of force the question is testing.