3.5 Newtons Laws and Momentum Flashcards
State Newton’s First Law:
An object will remain at rest or continue to travel with constant velocity unless acted upon by a resultant force.
State Newton’s Third Law:
When two objects interact, they exert equal and opposite forces on each other. These forces are always of the same type, and have the same magnitude but they act on different objects, and in opposite directions
What are the four fundamental forces?
Gravitational
Electromagnetic
Strong nuclear
Weak nuclear
State Newton’s second law:
The net force acting on an object is directly proportional to the rate of change of momentum, and is acting in the same direction
(In SI units, the constant k of proportionality is taken as equal to 1. )
What is the linear momentum of an object defined as?
The product of the objects mass and its velocity.
p=mv
What is impulse?
A measure of change in momentum.
impulse = ∆momentum = F∆t = m(v-u)
What is the area under a force time graph equal to?
The impulse over that time duration. Also, it is equal to the change in momentum.
State the principle of conservation of momentum?
For a system of interacting objects, the total
momentum in a specified direction remains constant, as long as no external forces act on the system
How is kinetic energy affected in a perfectly elastic collision?
The total kinetic energy of the system remains constant.
How is kinetic energy affected in an inelastic collision?
Some kinetic energy is lost to other forms, such as heat and sound energy.
What is conserved for both elastic and inelastic collisions?
Momentum and total energy.
What formula can we make using the principle of conservation of momentum?
What is required for this formula to work?
m1u1 + m2u2 = m1v1 + m2v2
One direction of movement must be considered negative.
Give an example of newton’s third law in effect?
The gravitational attraction of the Earth to a person standing on it, which is equal and opposite to the gravitational attraction of the person to the Earth.
What is the SI unit for momentum?
kgms^-1
What do we use to denote directions in one dimension for momentum calculations?
Positive and negative signs.
