Speed- measures the amount of distnace traveled in a given amount of time. (Doesn't measure the direction of the travel) How fast an object is going with respect to a frame of reference. You find speed by dividing distance by time. (Speed = distance/time) Instantaneous speed- the speed you are traveling at that moment, instead of an average. Motion- change in position of an object, relative to a frame of reference. Frame of reference- place or object that you assume is fixed. You observe how other objects move by comparing them to that frame of reference. Velocity- a measure of the speed and direction of an object. When speed, direction or both change velocity changes. If there is an increase in speed then positive acceleration can result. If there is a decrease in speed then negative acceleration (deceleration) can result. Acceleration= change in velocity/ time
Acceleration can involve a change in the direction an object is moving. (Change in velocity over time) If the change in velocity is an increase = positive acceleration. If the change in velocity is a decrease = negative acceleration or deceleration. Lesson 1.02h Speed, Velocity, and Acceleration
Scalar quantities- a measurement that has a size or magnitude but no direction. (speed, time, temperature & mass) Velocity and acceleration are NOT scalar quantities. Speed is always positive.
Vector quantity- has both magnitude and a direction. (Velocity, acceleration and force are examples) Magnitude- a measure of size, strength or quantity.
Lesson 1.03 The Laws of Motion
Natural Laws- Laws that are predetermined by nature and as a result are valid everywhere. Force- a push or pull applied to an object.
Balanced forces- Equal in size and opposite in direction, cancelling each other out. They do not cause a change in motion. Unbalanced forces- They work in the same direction. Cause a change in motion. The amount of force is not equal. Equal forces- Pushes in opposite direction, cancelling each other out so no movement occurs. The net force is zero. Friction- a force that works against the motion of an object. Force affects the movement of matter. Friction can occur between two solid objects and on objects moving through a liquid or gas. (Force can resist the motion of an object causing it to slow down) Law of Inertia- an objects resistance to a change in its motion. The greater the mass of an object, the greater the force needed to move it or stop it from moving. Net force- the total of all the forces acting on an object.
Newtons first law of motion- 2 principles. An object that is not moving will stay at rest unless an unbalanced force acts on it and an object in motion will stay in motion in a straight line and at a constant speed unless an unbalanced acts on it. It explains that a force is needed to change the motion of an object. Newtons second law of motion- it says that the acceleration of an object depends directly upon the net force acting on the object, and on the mass of the object. Newtons third law of motion- For every action there is an equal and opposite reaction that will occur. Lesson 1.03h The Laws of Motion
Momentum- its the mass of the object times its velocity.If the object is not moving, it has no momentum. Thw equation to find momentum is (momentum = mass x velocity) Momentum is a vector quantity because the object must be moving in a particular direction. (p=mv) Momentum will remain constant for objects interacting with one another within a system. Angular Momentum- The momentum characteristic of a rotating object, calculated by multiplying angular mass times velocity. They both deal with the motion of objects and the dependence of mass on motion. The main difference is that linear momentum deals with motion along a straight line, and angular momentum deals with rotational motion. Like linear momentum, angular momentum is conserved within a system. the angular momentum of an object is the product of the object’s mass times its velocity. However, for angular momentum, the mass is the angular mass, also known as the moment of inertia. Moment of inertia depends on the distribution of mass within an object. If the moment of inertia changes Lesson 1.04 Forces in Action
Gravity- a force of attraction between two objects that depends on two things: mass and distance. Distance: The greater the distance between the objects, the weaker the gravitational force between them. The strength of a gravitational force decreases with an increase in distance. Mass: The greater the mass of two objects, the greater the gravitational force between the objects. The Law of Universal Gravitation tells us that every object in the universe is attracted to one another by a force. Air resistance- caused by the friction between a falling object and the particles in air. The amount of air resistance a falling object experiences is based on the shape of the object and the speed at which it falls. All objects, regardless of their mass, experience the same acceleration when in a state of free fall. When the only force is gravity, and there is no air resistance, the acceleration is the same value for all objects. In order to remove air resistance, we would need to drop the objects without the presence of air. Scientists can use a container called a vacuum, a chamber from which nearly all air has been removed, to remove the friction caused by air resistance. Electromagnetic field- a field that is generated when charged particles such as electrons are accelerated. Electromagnetic forces- forces that occur when an Electromagnetic field interacts with electrically charged particles. Weak nuclear force- force involved in the radioactivity of some atoms. The weak nuclear force is responsible for different types of particle decay and radioactivity, including beta decay. Strong Nuclear Force is an attractive force that holds the nucleus of an atom together. It is associated with holding the protons and other subatomic particles together inside the nucleus. Lesson 1.05 Energy
Energy- the ability to change or move matter.
Potential energy- the energy that an object has because of its position or composition. Potential energy is sometimes called stored energy; you can think of it as stored energy waiting to be released. Kinetic energy- energy that an object has while in motion.
Radiant energy- the electromagnetic energy that travels in waves. Radiant energy is kinetic energy that includes light, x-rays, microwaves, and radio waves. Nuclear energy- the potential energy stored in the nucleus of an atom Mechanical energy- the energy an object possesses due to movement. Mechanical energy is kinetic energy because it it the movement from one position to another. Elastic energy- potential energy produced from stored materials. This is stored mechanical energy resulting from being stretched. Chemical energy- the potential energy stored in the bonds of molecules and compounds. Thermal energy- the internal kinetic energy in a substance caused by vibration of atoms and molecules. Thermal energy is also known as heat. Gravitational energy- potential energy an object has because of position. This is produced from gravitational force acting upon an object. Electrical energy- kinetic energy produced from the movement of an electric charge. Law of Conservation of Energy- energy cannot be created or destroyed Isolated system- a system where the total energy and mass is a conserved quantity. Closed system- a system where the total mass is a conserved quantity but ther total energy is not. Energy can enter or leave the system but matter cannot. Open system- a system where energy and mass can change, the amount of energy put in is not equal to the amount of energy put out. Both matter and energy are exchanged freely between the system and the surroundings. Latent- The amount of energy absorbed or released by a substamce during a phase change that occurs without a change in tempature. Lesson 1.06 Work and Power
Energy- defined as the ability to do work
There are three main components of work: force, movement, and cause. Work done on a flat surface can be calculated by multiplying force times distance. A greater force or a greater distance means a greater amount of work. work = force x distance
Work and force are directly related. This means that if you increase the force applied, you will increase the amount of work that will be done over the same distance. Work and distance are directly related. If you increase the distance, you will increase the amount of work that will need to be done with the same force. Work is measured in the units of joules.
Joules- the unit of measurement used to measure work.
Negative work- the force acts in the direct opposite direction of the motion in order to slow it down. Power- the rate at which work is done
When power is increased, more work can be done in a given amount of time or the same amount of work can be done in less time. Power = work/time
Power and time are inversely related. As the amount of power increases, the amount of time required to do the work would decrease. Power and work are directly related. As the amount of power increases, the amount of work able to be done also increases. The unit used to express power is watts. One watt is equivalent to 1 joule per second. Work must be measured in joules and time in seconds in order to calculate power in watts.