Chapter 7: Laws of Motion and Momentum Flashcards
What is Newton’s First Law?
Newton’s First Law states that if the resultant force acting on an object is zero and if the object is stationary, it will stay stationary. If the object is moving, it will stay moving with a constant velocity.
What is Newton’s Second Law?
Newton’s Second Law states that the net resultant force acting on an object is directly proportional to the rate of change of its momentum.
What is Newton’s Third Law?
Newton’s Third Law states that if Object A exerts a force on Object B, then Object B will exert a force back at Object A with a force that is equal in magnitude, opposite in direction and of the same type of force.
What are the 4 Fundamental Forces of Nature?
The 4 Fundamental Forces of Nature are Gravitational, Electromagnetic, Strong Nuclear and Weak Nuclear.
What is Momentum, and how can it be calculated?
Momentum is the Mass of the object multiplied by the Velocity it is travelling at. The equation for momentum is:
Momentum = Mass x Velocity of the object.
What is the Law of Conservation of Momentum?
The Law of Conservation of Momentum states that the total momentum within a closed system remains constant, the total momentum before a collision is the total momentum after a collision given that there are no external forces.
What is the equation for the conservation of momentum in a linear collision, assuming the two objects combine?
In a linear collision, the equation for the conservation of momentum is:
total momentum before = total momentum after
(m₁ v₁) + (m₂ v₂ ) = (m₁ + m₂)v
Note that the two objects combine to form one single mass, and can be rearranged to find missing values.
Note that one of the velocities MUST be negative if they are travelling in opposite directions.
This is an INELASTIC COLLISION.
What is an Elastic Collision, and what is conserved?
An Elastic Collision is a collision between two objects where the total kinetic energy between the objects remains the same before and after a collision.
In an elastic collision, the Total momentum, energy and kinetic energy is conserved.
What is the conservation of momentum equation for an inelastic collision?
In an Inelastic Collision, the equation for two objects is:
(m₁ v₁) + (m₂ v₂ ) = (m₁ + m₂)v
What is the conservation of momentum equation for an ELASTIC Collision?
For an Elastic Collision, the equation for conservation of momentum is:
(m₁ u₁) + (m₂ u₂ ) = (m₁ v₁ ) + (m₂ v₂)
What is the Conservation of Momentum equation for an object that splits into two pieces?
When an object explodes into two pieces, the equation is:
mu = (m₁ v₁) + (m₂ v₂)
What is Newton’s Second Law?
Newton’s Second Law states that the net resultant force acting on an object is directly proportional to the rate of change of momentum, and in the same direction.
What is the equation that links Force, Change in Momentum and Change in Time?
The equation that links Force, Change in Momentum and Change in Time is:
F = Δp / Δt
OR
F = (mv - mu) / t —-> F = m(v - u / t) —-> F = ma
This can be used when the mass of the object changes.
What is the definition of Impulse, and its equation?
Impulse is defined as the product of the force exerted and the time the force has been exerted for. Also known as the change in Momentum of an object. The equation for Impulse is:
Impulse = Force x Time
Note: This is needed in order to increase or decrease the momentum of a travelling object.
What is the area underneath a Force-Time Graph?
In a Force Time Graph, the area underneath the curve is equal to the impulse.
How do you find the total momentum when two objects collide?
When two objects collide, you add the momentum together,
If two objects are travelling in different directions after collisions, how do you find the missing angle or momentum of an object?
When two objects are travelling in different directions after collision, use a diagram to visualize the directions of the objects, fill in the given information and use resolving momentum to calculate the required value.
