science test

newton laws, forces, cells

Force

is a push or pull

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Inertia is...

the tendency for an object to resist a change in motion

Newtons 2nd Law of Motion says…

acceleration is based on an objects mass and force applied to it

Newtons 3rd Law of Motion says…

For every action there is an equal and opposite reaction.

F=mxa

the force (F) acting on an object is equal to the mass (m) of an object times its acceleration (a

Equation for Force

F=mxa

What units is a force measure in?

Newtons

Cause no change in motion

Balanced Forces

Cause an object to start moving, stop moving or change direction. The net force is greater than zero.

unbalanced forces

mass

measured in kilograms

Inertia depends on an objects…

mass

If there is more mass, then there is…

more inertia

If there is less mass, then there is…

less inertia

objects change their motion easily if they have

less inertia

objects have a harder time changing their motion if they have…

more inertia

A rocket takes of because of which Law?

3rd Law

Why do the blocks fly off the car when it crashed into the wall?

They are in motion and want to stay in motion.

Which of the rocks will have the greatest acceleration if pulled with 50 N of force?

Small rock

Which rock will need the most force to accelerate to 6 m/s^2?

Big rock

An object in motion or at rest…

not change its motion until an outside force acts on it

The balloon is an example of which law?

3rd Law

This is an example of which law?

1st Law

Which law is this an example of?

2nd Law 

A trebuchet launches a projectile because of which law?

2nd Law

An object at rest will remain at rest and an object in motion will remain in motion, unless acted on by an unbalanced force. \n Also called the "Law of inertia"

1st Law

The amount of matter in an object

Mass

A force that opposes or slows down motion

Friction

A force that always attracts or pulls objects toward each other without direct contact or impact

Gravity

Motion under the influence of gravity only. Example: Jumping off a rock into the ocean.

Free Fall

An object's change in position over time.

Motion

the rate at which an object moves.

Speed

the rate at which velocity changes.

Acceleration

describes both speed & direction.

Velocity

a measure of the force of gravity on the mass of an object

Weight

Controls the cells activities and contains the DNA.

Nucleus

Large balloon-like structures that hold water, food and waste that the cell doesn't need right away.

Vacuole

An organelle found in plant cells where photosynthesis occurs. It has folded structures that absorb sunlight.

Chloroplast

Only present in plant cells, some protists and fungi. It is much less flexible than the cell membrane and it gives the cell shape.

Cell Wall

Like the skin of the cell. It gets to decide what enters and exits the cell.

Cell Membrane

Jelly-like substance that fills most of the inside of the cell. It is always moving and takes oxygen and food to other parts of the cell.

Cytoplasm

Plant Cell

The basic unit of life of plants. Contains a cell wall and chloroplasts.

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Animal Cell

The basic unit of life of animals and humans. Doesn't have a cell wall or chloroplasts and has smaller vacuoles.

Organisms whose cells that do not have a nucleus or membrane-bound organelles.

Prokaryotes

Organisms whose cells have a nucleus and membrane bound organelles.

Eukaryotes

Mini-organ inside the cell that helps in performing various functions.

Organelle

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Plants use the sun's energy to convert water and carbon dioxide into sugars

Photosynthesis

The smallest unit that performs the functions of life.

Cell

Instructions for the cell. Like a recipe to make more cells.

DNA

An optical instrument used for magnifying small objects

Microscope

Made up of many cells that carry out a specific function

Tissue

Groups of tissues joined as a unit to serve a common function.

Organ

A group of organs that work together.

Organ System

Membrane that allows some things to pass through and others to not

Semi Permeable Membrane

Allows all molecules to pass or diffuse through

Permeable Membrane

Found in both eukaryotes and prokaryotes and produces proteins

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Found in both eukaryotes and prokaryotes and produces proteins

Powerhouse of the cell, organelle that is the site of ATP (energy) production

Mitochondria

A system of membranes that modifies and packages proteins for export by the cell

Golgi apparatus

An extensive membranous network in eukaryotic cells, continuous with the outer nuclear membrane and composed of ribosome-studded (rough) and ribosome-free (smooth) regions.

Endoplasmic Reticulum

An organelle containing digestive enzymes

Lysosome

Found inside the nucleus and produces ribosomes

Nucleolus

theory that eukaryotic cells formed from a symbiosis among several different prokaryotic organism

Endosymbiotic Theory

idea that all living things are composed of cells, cells are the basic units of structure and function in living things, and new cells are produced from existing cells

Cell theory

These are attached to the nosepiece and vary in size. The shortest lens is the least powerful and the longest lens is the most powerful. Often times people who make microscopes put different coloured bands to identify the different powers.

Objective Lenses

Lenses closest to the eye, typically magnify 10X

Ocular lens

controls the amount of light passing through the specimen

diaphragm (microscope)

smallest unit of an element that still represents that element

Atom

small area in the centre of an atom that contains its protons and neutrons

Nucleus

identifies the element; equal to the number of protons in the nucleus of the atom

Atomic Number

sub-atomic particle with a positive charge and found in the nucleus.

Proton

sub-atomic particle with no charge and found in the nucleus

Neutron

sub-atomic particle with a negative charge and found in the electron cloud outside of the nucleus

Electron

total number of protons and neutrons in an atom

Atomic Mass

Area in which the electrons are most likely to be found surrounding the nucleus

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Electron Cloud

a substance made of two or more different types of atoms

Compound

the simplest substance that is made of only one kind of atom.

Element

anything that has mass and takes up space.

Matter

properties that DO NOT CHANGE the makeup of a substance, only its appearance

Physical Change

an atom that has a charge because it has gained or lost electrons

Ion

two or more atoms of an element having the same number of protons, but a different number of neutrons.

Isotopes

properties that CHANGE the makeup of a substance

Chemical Change

chemical bond between two ions with opposite charges

Ionic Bond

bond where two or more atoms share electrons

Covalent Bond

electrons in the outermost shell of an atom that can participate in the formation of a chemical bond

Valence Electrons

In order to have a current flowing, a circuit must:

be closed

An electrical current in a metal wire is a flow of:

electrons

The higher the voltage supplied to a circuit:

the bigger the "push" received by electrons

When a charged battery is connected to a closed circuit, electrons flow from the ____________ terminal to the ____________ terminal.

positive; negative

Most electric heaters work by passing an electrical current through a component with very high resistance.

Resistance arises from the collisions between flowing electrons and atoms; when electrons slow down their energy is converted into heat

Recall which units are used to measure resistance.

Ohms

Adding resistance to a circuit will:

decrease the current

Identify what current (I) is equal to, according to Ohm's law.

voltage divided by resistance (I = V/R)

A student is investigating a circuit with a fixed total resistance. When the student doubles the voltage by adding another battery, the current will:

stop

The circuit in a particular toy car has a total resistance of 400 Ω and the battery is supplying 4 V. Calculate how much current, in amps (A), is flowing.

1600 A

An electrician measures the current flowing through a 1000 Ω resistor as 0.02 A. Calculate what the voltage supplied to this resistor must be.

50,000 V

A student constructs the circuit shown on the right and measures the current through the ammeter (A) to be 0.4 A. Assuming that the loudspeaker and wires have zero resistance, determine the value of the resistor.

30 Ω

A student varies the voltage across a resistor of unknown value and measures the current. The data is graphed on the left. Determine the value of the unknown resistor.

400 Ω

What is the unit of measurement for electrical current?

Amperes

When resistance in a circuit increases, what happens to the current?

It decreases

What happens to the current in a circuit if you increase the voltage while keeping the resistance constant?

The current increases

In a series circuit, how do the resistance values add up?

They add up