Physics — Laws of Motion

Inertia is the inherent property of matter that causes it to resist changes in its state of motion, as described by Newton's First Law.

Momentum is the product of mass and velocity. Since velocity is a vector, momentum is also a vector quantity.

This illustrates the Law of Inertia (First Law); the carpet moves due to the force, but the dust tends to remain at rest.

The passenger's body is in a state of motion and continues to be so due to the inertia of motion even after the bus stops.

According to F=ma, 1 Newton = 1 kg × 1 m/s², which is 1 kg·m/s².

Rocket propulsion follows the Law of Conservation of Momentum (a direct consequence of Newton's Third Law).

Momentum (p) = mv. If m becomes 2m and v becomes v/2, then p' = (2m)(v/2) = mv. The momentum remains constant.

By increasing the time of impact, the rate of change of momentum is reduced, which decreases the force exerted by the ball on the hands.

Action and reaction forces always act on two different bodies simultaneously; hence, they cannot cancel each other out.

According to Newton's First Law, if the velocity is constant, the acceleration is zero, implying the net force is zero.

Newton's First Law of motion is famously known as the Law of Inertia.

Impulse is defined as the product of force and time, which is equal to the change in momentum (Impulse-Momentum Theorem).

For an object to be in translational equilibrium, the resultant (net) force acting on it must be zero.

Weight (W) = mg = 10 kg × 9.8 m/s² = 98 N.

Weight is the force Earth exerts on the book. By Newton's Third Law, the reaction is the force the book exerts on the Earth.

The recoil of a gun is a result of the conservation of momentum; the backward momentum of the gun equals the forward momentum of the bullet.

From F=ma, acceleration (a = F/m) is directly proportional to the applied force (F) for a given mass.

Newton's First Law states that an object in motion stays in motion with the same speed and in the same direction unless acted upon by an external force.

The swimmer pushes water back (action), and the water pushes the swimmer forward (reaction), which is Newton's Third Law.

According to the Law of Conservation of Linear Momentum, the total momentum of a system remains conserved if no external force acts on it.

Although the speed is constant, the direction of motion is constantly changing in circular motion, resulting in centripetal acceleration.

Impulse is defined as the product of force and time, so its unit is Newton-second (N·s), which is equivalent to kg·m/s.

Newton's Second Law mathematically states that F = dp/dt, meaning the net force is the rate of change of momentum.

Since F = dp/dt, if F = 0, the change in momentum (dp) is 0, implying the momentum remains constant.

According to Newton's First Law, if the net force is zero, an object will maintain its state of constant velocity (uniform motion).

Due to inertia, the ball shares the horizontal velocity of the train, so it follows a parabolic path relative to the ground and lands back in the passenger's hand.

Mass is the quantitative measure of inertia; the greater the mass, the greater the resistance to change in motion.

If velocity is constant (zero acceleration), the net force acting on the body must be zero according to Newton's laws.

Newton's Third Law states that for every action, there is an equal and opposite reaction, describing mutual interaction between two bodies.

In a vacuum, air resistance is absent. All objects accelerate at the same rate 'g', regardless of their mass.

This is the mathematical expression of Newton's Second Law of Motion: Force equals the product of mass and acceleration.

According to Newton's Third Law, the horse pushes the ground backward, and the ground pushes the horse forward (reaction force), enabling movement.

An inertial frame is one that is not accelerating. A car accelerating on a road is a non-inertial frame of reference.

Since a = F/m, if F is doubled while m is constant, acceleration a will also double.

The conservation of momentum is a consequence of Newton's second and third laws acting together in a system.

When a bullet is fired, it gains forward momentum, and the gun recoils backward to keep the net momentum zero.

Using F = ma, a = F/m = 20/5 = 4 m/s².

The gravitational force exerted by the Sun on the planet provides the necessary centripetal force for the orbital motion.

A force acting for a very short interval of time is known as an impulsive force, producing a large change in momentum.

Newton's Second Law (F=ma) is modified in non-inertial frames to include pseudo forces, which arise due to the acceleration of the frame itself.

According to the property of center of mass, if the sum of external forces is zero, the center of mass moves with a constant velocity (or remains at rest if initially at rest).

Jerk is the time derivative of acceleration, making its SI unit meters per second cubed (m/s³).

The block will remain at rest because the applied force is just enough to overcome static friction to reach the point of impending motion, but not yet to induce acceleration.

A force acting perpendicular to the velocity (like centripetal force) changes only the direction of motion, not the magnitude of the velocity (speed).

Impulse is defined as Force × time (N·s). Since F = ma (kg·m/s²), Impulse is (kg·m/s²) × s = kg·m/s, which is the unit of change in momentum.

By throwing an object, he gains momentum in the opposite direction due to the conservation of linear momentum, allowing him to slide towards the shore.

From Newton's Second Law, F = ma, therefore F/a = m. Mass is a quantitative measure of inertia.

Terminal velocity is reached when the drag force equals the gravitational force; since the net force is zero, acceleration becomes zero.

Gravitational force is a non-contact (field) force, whereas normal force, friction, and tension are contact forces arising from atomic interactions.