3.5. Newton's Laws of Motion and Momentum

What are Newton's three laws of motion?

They are universal laws that can model the motion of objects.

What is Newton's first law?

An object will remain at rest or continue to travel with constant velocity unless acted upon by a resultant force.

What does Newton's second law state?

The net force acting on an object is directly proportional to the rate of change of momentum, acting in the same direction.

What is the formula for Newton's second law?

F = (dp/dt), where F is net force and dp/dt is change in momentum over time.

What is Newton's third law?

When two objects interact, they exert equal and opposite forces on each other.

What forces obey Newton's third law?

All four fundamental forces: gravitational, electromagnetic, strong nuclear, and weak nuclear forces.

What is linear momentum?

Linear momentum, p, is defined as the product of an object's mass, m, and its velocity, v: p = mv.

What is the SI unit for momentum?

The SI unit for momentum is kg*m/s (kilogram meter per second).

Why is momentum considered a vector quantity?

Because momentum has both direction and magnitude.

What does the equation F = ma represent?

It is a special case of Newton's second law where mass remains constant during motion.

How is impulse defined?

Impulse is defined as the product of force and the time for which it acts.

What is the relationship between impulse and momentum?

Impulse is a measure of change in momentum.

What is the formula for impulse?

Impulse = F * Δt = Δp, where F is force and Δt is time.

What does the area under a force-time graph represent?

It represents the impulse over that time duration and is equal to the change in momentum.

What is the principle of conservation of momentum?

The total momentum in a specified direction remains constant, as long as no external forces act on the system.

What happens during a perfectly elastic collision?

The total kinetic energy of the system remains constant.

What happens during an inelastic collision?

Some kinetic energy is lost to other forms, such as heat and sound energy.

What is conserved in both types of collisions?

Total energy and total momentum are conserved.

For a one-dimensional collision, what does the conservation of momentum state?

m1u1 + m2u2 = m1v1 + m2v2, where u is initial velocity and v is final velocity.

In a two-dimensional collision, how is momentum treated?

Momentum must be considered separately in both the x and y directions.

How can external forces affect momentum?

If external forces are acting, total momentum may not be conserved.

What is the significance of the negative sign in momentum equations?

It indicates direction for objects moving in the opposite direction.

What does the formula p = mv identify about momentum?

It shows that momentum is dependent on both mass and velocity of the object.

How is change in momentum expressed mathematically?

Change in momentum is expressed as Δp = m(v - u), where u is initial velocity and v is final velocity.

What can be said about the interaction forces in Newton's third law?

The interaction forces are equal in magnitude and opposite in direction.

What does 'net force' refer to in Newton's second law?

Net force refers to the total force acting on an object after all forces are combined.

What role does time play in the concept of impulse?

Time is a key factor, as impulse is the product of force and the duration of time it acts.

What is momentum transfer during collisions?

Momentum transfer occurs when two or more objects collide, exchanging their momenta.

What is required for the conservation of momentum to hold true?

There must be no external forces acting on the system.

What is an example of a non-conservative collision?

An inelastic collision where kinetic energy is not conserved and transformed into other energy forms.

When dealing with momentum in a system, what must be considered?

The total momentum before interaction must be compared to the total momentum after interaction.

What are the four fundamental forces in nature?

Gravitational, electromagnetic, strong nuclear, and weak nuclear forces.

What is the significance of 'equal and opposite' forces in physics?

It establishes that forces acting between two objects are always balanced.

How is the mass used in the formula F = ma?

Mass is used as a constant factor when evaluating the force on an object under constant acceleration.

What does momentum depend on besides mass?

Momentum also depends on the velocity of the object.

Describe the behavior of momentum in a closed system.

In a closed system, the total momentum before a collision is equal to the total momentum after the collision.

What is required for a collision to be classified as elastic?

Both kinetic energy and momentum must be conserved.

What is the relation between force and the change of momentum with respect to time?

Force is equal to the rate of change of momentum over time.