Mind map :: Chapter 9: Force and laws of motion

Mind Map: Force and Laws of Motion

• A force is a push or pull on an object, causing a change in its state of motion or shape.
• It is a vector quantity, meaning it has both magnitude and direction.

• 1️⃣ Can change the state of motion (speed up, slow down, stop).
• 2️⃣ Can change the shape of an object.
• 3️⃣ Can cause deformation in elastic or inelastic materials.
• 4️⃣ Can cause the rotation of an object if the force is applied off-center (torque).

• Balanced forces result in no change in the motion of the object.
• They are equal in magnitude and opposite in direction.
• Example: A book resting on a table, where the gravitational force is balanced by the normal force.

• Unbalanced forces result in a change in the object's motion (speed or direction).
• Examples: A car accelerating, a person pushing a sled.
• Unbalanced forces lead to acceleration or deceleration of an object.

• An object remains at rest or in uniform motion unless acted upon by an external force.
• This law explains the concept of inertia, where objects resist changes in their motion.
• Example: A ball rolling on a flat surface will continue rolling unless acted upon by a force (e.g., friction).

• F = m × a
• SI Unit: Newton (N) = kg·m/s²
• The second law defines the relationship between force, mass, and acceleration.
• It shows that the force applied to an object is proportional to its mass and the acceleration produced.
• Example: Pushing a lighter object will cause more acceleration than pushing a heavier object with the same force.

• For every action, there is an equal and opposite reaction.
• Example: When you push against a wall, the wall pushes back with an equal force in the opposite direction.
• This law explains phenomena like rocket propulsion, where gases are expelled backward, and the rocket moves forward.

• The total momentum of an isolated system remains constant before and after a collision or interaction.
• Momentum is conserved when there are no external forces acting on the system.
• Example: In a two-body collision, the combined momentum of both objects before and after the collision remains the same.

• m₁ u₁ + m₂ u₂ = m₁ v₁ + m₂ v₂
• Momentum (p) = Mass × Velocity (kg·m/s)
• Where m₁, m₂ are masses, u₁, u₂ are initial velocities, and v₁, v₂ are final velocities.

• 1️⃣ Momentum (p) = Mass × Velocity
• 2️⃣ Initial Momentum = m × u
• 3️⃣ Final Momentum = m × v
• 4️⃣ Rate of change of momentum = (m × v - m × u) / t
• 5️⃣ Since acceleration (a) = (v - u) / t, we get:
• F = m × a
• Thus, force is the rate of change of momentum.

• 1️⃣ Two objects of masses m₁ and m₂ move with velocities u₁ and u₂.
• 2️⃣ Initial Momentum = (m₁ × u₁) + (m₂ × u₂)
• 3️⃣ After collision, velocities change to v₁ and v₂.
• 4️⃣ Final Momentum = (m₁ × v₁) + (m₂ × v₂)
• m₁ u₁ + m₂ u₂ = m₁ v₁ + m₂ v₂
• The total momentum of the system remains conserved before and after the collision.