Physics Unit 1, 2, 3, 4, 5

Impulse and change in "p"

"p" is momentum and Impulse is a change of momentum that can be calculated with I=Ft or Ft=∆(m•v)

Calculate mass or velocity after collision

*if on phone hold sideways for formula to fit properly Use this formula, A and B will be objects in this example. A+B=AB mass. (__kg)+(__kg)=(__kg) velocity(__m/s)+(__m/s)=(__m/s) You will times the mass and velocity of A. Do the same for B. Add them, there should be missing values, that's what you'll be solving for. Ex. A+B=AB mass. (_5_kg)+(_5_kg)=(_10_kg) velocity(_2_m/s)+(_0_m/s)=(_x_m/s) A=10kg.m/s B=0kg.m/s AB=10xkg.m/s 10+0=10x 10=10x ÷ by 10 x=1m/s is the velocity after the collision. Multiply by 10kg, AB, and the momentum is 10kg.m/s after the collision, the momentum was conserved. *This was for an Inelastic collision but the formula could be changed to A+B=A+B for an elastic collision or even AB=A+B if they separated later on.

Leverage and conservation of energy

-A lever is a machine consisting of a beam or rigid rod pivoted at a fixed hinge, or fulcrum. ... A lever amplifies an input force to provide a greater output force, which is said to provide leverage. The ratio of the output force to the input force is the mechanical advantage of the lever. -can't get more work out than you put in. Energy has to be conserved.

net force and equilibrium

-A net force is defined as the sum of all the forces acting on an object. -A condition in which all influences acting cancel each other, so that a static or balanced situation results. In physics, equilibrium results from the cancellation of forces acting on an object.

Free Fall, distance, velocity and acceleration

-Free fall, free fall is any motion of a body where gravity is the only force acting upon it. -Distance, a scalar quantity that refers to "how much ground an object has covered" during its motion. -velocity, a physical vector quantity; both magnitude and direction are needed to define it. -acceleration, is the rate of change of velocity of an object with respect to time. An object's acceleration is the net result of any and all forces acting on the object, as described by Newton's Second Law.

Friction, kinetic, and static

-Friction is a force that holds back the movement of a sliding object. -Kinetic Friction is a force that acts between moving surfaces. An object that is being moved over a surface will experience a force in the opposite direction as its movement. The magnitude of the force depends on the coefficient of kinetic friction between the two kinds of material. -Static Friction is the friction that exists between a stationary object and the surface on which it's resting. A frictional force occurs when you try to push an object alongside a surface. Once the objects have already started moving, kinetic friction takes over.

calculate normal force if given weight or mass

-Given weight, it's the same as the weight. Ex. 25N pushing down on the ground, then the ground pushes up 25N. -Given mass, convert to weight, then do the weight thing mentioned above. Ex. 2kg•10m/s^2 (force of gravity rounded to 10 instead of 9.8)= 20N down and 20N up.

Inertia (compared to constant velocity)

-Inertia is the resistance of any physical object to any change in its state of motion. This includes changes to the object's speed, direction, or state of rest. Inertia is also defined as the tendency of objects to keep moving in a straight line at a constant velocity. -when an object travels the same distance every second, then the object is said to be moving with constant velocity.

speed, instantaneous and average

-Speed, being a scalar quantity, is the rate at which an object covers distance. -The average speed is the distance (a scalar quantity) per time ratio. Speed is ignorant of direction. -Instantaneous Speed is the speed of an object at a particular moment (instant) in time.

Vector, scaler and examples

-Vector is a quantity that has both magnitude and direction. It is typically represented by an arrow whose direction is the same as that of the quantity and whose length is proportional to the quantity's magnitude. Ex. displacement, velocity, acceleration, momentum, force, and weight. -Scalers are quantities that are fully described by a magnitude (or numerical value) alone. Ex. length, area, volume, speed, mass, density, pressure, energy, work, and power.

Work, Power, Conservation of energy, KE, and PE

-Work is done when a force that is applied to an object moves that object. The work is calculated by multiplying the force by the amount of movement of an object (W = F * d). A force of 10 newtons, that moves an object 3 meters, does 30 n-m of work. -Power is the rate of doing work, the amount of energy transferred per unit time. ... In the International System of Units, the unit of power is the joule per second (J/s), known as the watt in honour of James Watt -Conservation of energy system in a given frame of reference remains constant — it is said to be conserved over time. Cannot be created or destroyed. -Kinetic Energy of an object is the energy that it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes. -Potential Energy is the energy that is stored in an object due to its position relative to some zero position. An object possesses gravitational potential energy if it is positioned at a height above (or below) the zero height.

Momentum and impulse

-momentum= the product of its mass times its velocity. It is a vector quantity. ... The basic definition of momentum applies even at relativistic velocities but then the mass is taken to be the relativistic mass. The most common symbol for momentum is p. The SI unit for momentum is kg m/s. -impulse is the change of momentum of an object when the object is acted upon by a force for an interval of time. So, with impulse, you can calculate the change in momentum, or you can use impulse to calculate the average impact force of a collision.

3 special triangles

30°, 60°, 90°/ 45°, 45°, 90°/ 3, 4, 5

Momentum is conserved in ___ collisions

All

Newton's First Law

An object continues in uniform motion in a straight line/ at rest unless a resultant force acts. Also known as inertia.

Conservation of momentum

For a collision occurring between object 1 and object 2 in an isolated system, the total momentum of the two objects before the collision is equal to the total momentum of the two objects after the collision.

Newton's Third Law

For every action there is an equal and opposite reaction.

Newton's Second Law

Force = Mass x Acceleration

action and reaction

Forces exist only in pairs. The size of the forces on the first object equals the size of the force on the second object.

Horizontal projectile example (time to fall if given height, and distance traveled horizontally given horizontal speed and time to fall)

If given height use the free fall equation, h=5t^2 and solve to get time. To get distance traveled use the equation, horizontal speed•time.

monkey and Hunter example

Imagine a hunter in the jungle who has just spotted a monkey grasping a tree branch above him. To avoid more troubling moral questions, let's assume that the hunter must capture the monkey to treat it for a disease before releasing it back into the wild. The hunter also knows that the monkey will reflexively drop from the branch immediately after the hunter pulls the trigger. Immediately after the bullet exits the barrel, the monkey will begin his free fall toward the ground. However, the hunter doesn't know exactly how fast the tranquilizer bullet will travel after leaving the gun — he just knows it'll move fast. With all of this in mind, where should the hunter aim? Where would you aim? Three choices arise: 1. Aim above the monkey 2. Aim directly at the monkey 3. Aim below the monkey Intuitively, you might think that the hunter needs to aim below the monkey due to how fast the bullet moves. If he shoots at or above the monkey, won't the bullet whiz over its head as the monkey falls toward the ground? But that's wrong. The correct answer is 2: Aim directly at the monkey. Once the bullet exits the gun, there's only one force acting on it with any significance: gravity (and some negligible air resistance in this case). Likewise, only gravity will act upon the monkey after he loosens his grasp

horizontal part

Imagine a triangle with a 90° angle, the horizontal part of it is the horizontal part, as the name implies, say a cannonball being shot, it's constant velocity, is the horizontal part.

vertical part

Imagine a triangle with a 90° angle, the part going down, not the hypotenuse, is the vertical part in let's say a cannonball being shot and forget about constant velocity as it travels, but focus on free Fall of the cannonball as it travels, how much it falls a second.

Horizontal and Vertical velocity are___________.

Independent

Mass vs. Weight

Mass - how much matter / Weight - matter x gravity

How rockets are propelled

Rockets and engines in space behave according to Isaac Newton's third law of motion: Every action produces an equal and opposite reaction. When a rocket shoots fuel out one end, this propels the rocket forward — no air is required.

Energy

The ability to do work (J)

gravitational acceleration

The acceleration of an object due to gravity. 9.8 m/s^2

Terminal velocity: calculate air resistance force if given weight

The air resistance is equal to the weight

Displacement from velocity graph

The area under the line

Gun/Bullet action reaction, force and accleration

The bullet goes forwards, but pushes back creating recoil. The action is bullet going forwards, reaction is recoil. Force of bullet will be the same as gun/shooter, due to law of conservation of momentum. After the bullet is shot, due to gravity, the bullet's direction changes, and due to drag forces, the bullet's speed decreases.

Work is the ________ __ ______ from one form to another

Transfer of energy

Slope of position vs time graph

Velocity

Equations for Work, Power, conservation of energy, KE, and PE

Work= Force•Distance Power=Work÷time Kinetic Energy= 1/2 mass•velocity^2 Potential Energy= mass•gravity(9.8)•height For conservation of energy, look at card: calculate mass or velocity after collision.

slope of a velocity vs time graph

a= change of v/time acceleration

calculate acceleration, force or mass, if given the other two

a=F/m, F=m•a, m=F/a

collisions, elastic, inelastic

collisions can either be elastic,meaning they conserve both momentum and kinetic energy, or inelastic, meaning they conserve momentum but not kinetic energy. -Elastic doesn't stick to the other object, Inelastic does.

Calculate average speed

divide distance by time

a= F/m

formula for acceleration

Calculate free Fall distance given time

h=5t^2, plug in the time value for t

Calculate free Fall speed given time

h=5t^2, then plug the h into the D=s•t equation for D. Divide by the time and you should get speed.

acceleration vs time graph

horizontal line shows constant acceleration

calculate initial momentum before collision

p=m•v

Pressure

the amount of force exerted per unit area of a surface. It's units are Pascal's.

Force due to gravity is your weight

w(Newtons) = mass(kilograms) x g(m/s^2)

calculate work needed to lift a weight to a height

w=F•d change to w=F•h the weight if not in Newtons, convert to Newtons by multiplying by force of gravity(9.8)or(10) if teacher allows you to round

calculate the weight of an object given it's mass

weight=mass•gravity