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| force of gravitational pull working on an object; it increases/decreases as gravity's pull increases/decreases |
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| the amount of space an object occupies; can be calculated using a formula (for regular objects like cubes and prisms)or by using water displacement (solids that are irregular shaped); or measuring in a graduated cylinder (liquids) |
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| the ratio of an object's mass to its volume; calculated by dividing mass by volume. Water has a density of 1.0 g/mL. Objects with density of less than 1 will float in water; objects with a density greater than 1 will sink in water. |
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| amount of matter an object contains; it does not change unless part of the object falls off or another portion is added |
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| occurs when a force moves an object over a distance in the direction the force is exerted. (ex: a ball is thrown to the left and the ball moves to the left). |
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| a metric unit of force; abbreviated N |
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| abbreviated J, it is a unit associated with work. It is equal to a Newton meter. |
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| Work = force times distance (used to calculate work) where work is J, force is N, and distance is meters (m) |
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| the rate at which work is done; measured in Watts (W) which is joules per second; calculated by dividing work by time |
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| Power equals work divided by time where power is in W; work is in J and time is in s |
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| an object that makes work easier; there are 6 types (lever, inclined plane, wedge, screw, wheel and axle, and pulley); they can change the direction of a force, change the magnitude of a force or increase the distance over which a force is exerted. |
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Definition
| a rigid bar (curved or straight) that rotates on a fixed point called a fulcrum; come in three classes |
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| made up of two circular objects that are connected and turn at the same time; examples include wheels and axles on vehicles like cars and buses, waterwheels ; can increase the size of the input force |
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| examples include axes and wood splitters; change the direction of the input force |
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Definition
examples include ramps
decreases the amount of force that must be input but increases distance of force |
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Definition
examples include crow bars and see saws;
a rigid object that rotates on a fulcrum; there are three classes |
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Definition
| input force is greater than output force; mechanical advantage is always less than 1; the fulcrum is at one end of the lever and the output force is at the other end with the input force in the middle; example: hammer, fishing rod, baseball bat |
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Definition
| a wheel with a groove holds a belt or rope that is used to move an object |
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| has a mechanical advantage of 1; the pulley is fixed to a surface; this changes the direction of the force but does not increase the force |
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Definition
| the pulley is attached to the load; it has a mechanical advantage of 2. |
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| a system of pulleys that include a fixed pulley and movable pulleys; mechanical advantage is more than 2. |
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Definition
| examples include wheel barrows, bottle openers. The fulcrum is at one end with the input force at the other and the output force in between the two. Input and output force move in the same direction. |
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fulcrum movement can change how much input force must be used to move the load; input force and output force go in opposite directions; fulcrum is between the input and output forces;
example: see saw, crow bar |
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Definition
| term used to describe substances that are poisonous; symbol is skull and cross bones |
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| term used to describe materials that catch fire easily when exposed to sparks or flames; safety symbol is a flame |
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| safety symbol is a flame with a diagonal line across it; when this symbol is showing in the lab, no flames, sparks or other sources of ignition should be around |
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Definition
| this safety symbol is a garbage can with a diamond on it; when this symbol is shown, it means that there are special directions for disposing (getting rid of) laboratory materials |
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| term used to describe materials that have the ability to erode or eat away at materials they come into contact with; symbol is test tube with drops and a table with a hole in it |
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Definition
| safety symbol looks like a bottle or container with vapor coming from it; when this symbol is shown, care must be taken to not inhale vapors and work in a well-ventilated area |
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Definition
| in an experiment, this is what is measured; usually follows the "then" in the hypothesis; (ie. if you are measuring the effect of water on plant growth, the dependent variable is would be amount of plant growth) |
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Term
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| in an experiment, the part that is controlled (ie. if testing the effect of water on plant growth, the independent variable would be the amount of water given to the plant); usually follows the "if" in the hypothesis |
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| the amount that a machine multiplies force; usually found by dividing output force by input force |
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| how fast an object is moving; does not include direction |
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| change in a position of an object when compared to a non-moving reference point. Example: a van driving down the street past a light pole could have its motion compared to the light pole (non-moving object) |
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| similar to speed; however, velocity is the speed of an object and the direction in which it is moving |
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| change in velocity; this can include either a change in speed OR also a change in direction; depends on the amount of force used and the mass of object being moved |
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| a decrease in velocity; also known as negative acceleration |
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| a push or a pull; can be balanced or unbalanced |
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| total of all forces on an object |
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| any situation when the net force does not equal zero; that is, forces in one direction are greater than the forces coming from the opposite direction; result is movement |
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Definition
| any situation where the total net of forces are zero; that is, all forces are equal on an object; this can happen when an object is still or moving at a constant velocity (not accelerating or decelerating) |
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| occurs when two surfaces come in contact with one another; it works against motion; can be positive (sand in paint on a slick surface) or negative (friction building up in an engine) |
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Term
| What does the slope of a distance/time graph show you? |
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Definition
| It shows you the speed at which the object is moving. |
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| How can you tell an object is not moving if you are looking at a distance/time graph? |
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Definition
| If you are looking at a distance/time graph, an object that is not moving will have a line that is straight across (horizontal). |
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| What does a downward slanting line mean on a distance/time graph? |
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| It means the object is coming closer to where it started; it may be rolling backwards or just moving back to where it started (example: a person running back home) |
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| What does the slope of a speed (or velocity) and time graph show you? |
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| The slope of a speed (or velocity) and time graph shows you if the object is accelerating. The steeper the line, the more it is accelerating or decelerating. |
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| If you see a horizontal straight line on a speed (or velocity) and time graph, what does it mean? |
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Definition
| It means that the object is moving at a constant speed. It has balanced forces (net force of 0). |
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| If a line is curved on a distance-time graph, what does it mean? |
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| It means that the object is accelerating. |
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Term
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Definition
| "mass in motion"; this is calculated by multiplying the mass and the velocity. |
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Term
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| a drawing which shows the forces acting upon an object |
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| formula for calculating momentum |
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Definition
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| formula for calculating speed or velocity |
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Definition
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Definition
| the tendency of an object to stay at rest or in motion until OR unless an unbalanced force works upon it |
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| Newton's 1st Law of Motion |
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Definition
| An object at rest (or in motion) will stay at rest (or in motion) unless it is acted upon by another force; known as law of inertia |
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Term
| Newton's 2nd Law of Motion |
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Definition
| the greater the mass of an object, the greater force must be applied to the object in order to make it accelerate |
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Term
| Newton's 3rd Law of Motion |
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Definition
| For every action, there is an equal and opposite reaction; for every force applied to an object, that object exerts the same force back on the source of the force |
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Term
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Definition
| the amount that a simple machine multiplies an input force; it can be greater or less than 1 |
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Term
| mechanical advantage of wheel and axle |
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Definition
radius of wheel / radius of axle
greater than 1 because wheel must be larger than axle |
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Term
| mechanical advantage of inclined plane |
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Definition
| distance of incline (length of hypotenuse of triangle) divided by the height the object is raised (height of leg of triangle) |
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Term
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Definition
| a measure of how close a measurement is to its real value; if you are an accurate shooter, you hit the center of the bullseye |
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Term
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Definition
| means how exact you are; the smaller the measurement unit, the more precise. 12 1/4 inches is more precise than 1 foot; the more digits after the decimal point the more precise. 12 is less precise than 12.0 is less precise than 12.01 is less precise than 12.009 |
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Definition
| object is moving at a constant speed |
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| object is slowing down (speed/time graph) |
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| object is stopped (speed/time graph) |
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