Please enable JavaScript.
Coggle requires JavaScript to display documents.
Forces and the Laws that Define them, image - Coggle Diagram
Forces and the Laws that Define them
Newtons Laws
2nd Law: The net force acting upon an object is equal to its mass times acceleration or F = ma. This equation is most useful and makes more sense when arranged to solve for acceleration: a = m/F
Mass is a measure of how much matter is in an object
Force is a measure of mass and acceleration used to make free body diagrams
Acceleration is the speed at which an object gains velocity
3rd Law: When a force is applied to an object that object exerts a force back on what is pushing with equal magnitude in the opposite direction.
This law is what makes something at rest on the ground being acted upon only by gravity not accelerate. If gravity pulls an object down then the surface it is on exerts and equal and opposing force on the object.
1st Law: If you do not put a force on an object it will not accelerate it can only stay at a constant velocity or at rest.
This means that if an object has all balanced forces acted upon it it will stay in a state of constant velocity or rest unless the forces become unbalanced.
Friction
Kinetic
Kinetic friction affects an object when that object is already moving along said surface. Kinetic friction is always less than static because the grooves slide over each other and don't sink as easily which applies less resistance to applied force.
Friction Equation: F = [mu]N
The frictional coefficient is how we write the amount of friction as a number and has static and kinetic variants. The Static frictional coefficient is always higher than the coefficient of kinetic friction on an object.
The normal force is just the amount of force the surface has to exert on the object in order to keep it from accelerating downwards. This is calculated with Nf = mg or the normal force is equal to mass times gravity
The frictional force is the amount of force friction applies on an object in the opposite direction of it's movement.
Static
Static friction is at play when an object at rest on the ground or up against another object is being acted on by a force. Static friction is higher because at a microscopic level there are little grooves in the surfaces with contact. When the objects are still the grooves settle into each other and there for grant higher resistance when it is under an applied force.
Drag
Drag equation: Fd = 1/2p
v^2
Cd*A
v is the velocity of the object in motion. In this equation when the speed increases the drag increases exponentially.
A is the cross sectional are of the object. Which ever directing the resistance is acting in this area is essentially the silhouette of the object
p is the density of the substance an object is traveling trough. The denser the more resistance.
Cd is the drag coefficient. This like the friction coefficients is a value calculated in a lab that we use to calculate the force of drag on most objects. This value is calculated in a controlled environment like a wind tunnel.
Fd is the drag force which is the amount of newtons applied in the opposite direction of motion due to drag
Drag is the term for air resistance or friction on an object as it collides with particles in the air. Drag only affects objects in motion and is dependent on many different variables.
Free Body Diagrams
Free body diagrams are what we use to show what forces are acting upon an object.
Free body diagrams can be very useful when trying to predict what an object will do in the future and is a good way to keep track of variables
