Finals Flashcards
Reference point
Point used to determine if an object is in motion
Motion
Moving a distance away from a reference point
Speed
Distance in a given amount of time
Meters/seconds
Average speed
The overall rate of speed at which an object moves; calculated by dividing the total distance an object travels by the total time
Velocity
Speed in a given direction
Acceleration
Rate at which velocity changes
Slope on a distance versus time graph
Zero slope or positive. Speed is the slope
Slope in speed versus time graph
Negative positive whatever. It is acceleration.
Force
Push or pull
Newton
Unit for force
kg•m/s^2
1st law of motion
Law of inertia
2nd law
Mass x acceleration=force
3rd law
Actio/reaction. Equal but opposite force
Net force
Combination of all balanced and unbalanced forces
Unbalanced force
Force that is greater on one side. Start moving, stop moving, or change direction
Balanced force
Equal forces; doesn’t move
Friction
Force on moving objects when moving surfaces rub together
Static, sliding, rolling, fluid
Frictions, friction on: unmoving objects, when one object slides over, rolls over, and friction in a fluid
Gravity
Force that pulls objects to the centre of earth and together
Law of universal gravitation
Every object has a force of gravity in the universe.
Mass
Matter in an object
Weight
Force of gravity on an object
Free fall
Only force is gravity. The motion of a falling object when the only force acting on it is gravity
Air resistance
A type of fluid friction experienced by objects falling through the air
Terminal velocity
The greatest velocity a falling object can achieve. Distance an objects falls is equal to the weight of the object
Inertia
The tendency of an object to resist a change in its motion
Momentum
“Quantity” mass x velocity.
Law of conservation of momentum
Hit something the momentum stays the same. Aside from outside forces, the total momentum of objects that interact does not change
Pressure
Force in a given area (foot print)
Pascal
Unit for pressure
Fluid
Liquids and gases–something that easily moves
Buoyant force
Upward force opposite gravity pushing on objects.
Archimedes principle
Buoyancy of an object is equal to the weight of the water displaced
Density
How tight something is . Find!!’
Pascals principle
Pressure applied on a fluid is equally transmitted to all parts of a fluid
Hydraulic
A system that multiplies force by transmitting force from a small surface area to a bigger surface area. Pressure does not change. It stays the same
Bernoulli’s principle
The faster a moving fluid moves the less pressure it exerts
Lift
Upward force
Work
Force * distance. Same direction.
Joule
Unit for work
Power
Work in a given time
Watt
Unit for power =746 watts in one horsepower
Machine
Something made to simplify human work
Input force
Effort. Force done on a machine
Output force
Load (look up in depth) force done by a machine
Input work
Input force times input distance
Output work
Output force times output distance
Output work can never be greater
Mechanical advantage
Number of times a machine increases a force exerted on it
Efficiency
Compares output work to input work as a percent
Inclined plane
Flat, sloped surface
Wedge
Device that is thick at one end and tapers to a thin edge. You move the inclined plane itself not he object.
Screw
Inclined plane wrapped around a cylinder. Increases distance over which you exert the input force.
1st class lever
Output fulcrum input force. See-saw, scissors, pliers, can. *these levers increase force if its near the output force. If near input, it increases distance.
2nd class lever
Effort output fulcrum. Wheelbarrow, doors, nutcrackers, bottle openers. Increase force but do not change direction of the force.
3rd class levers
Fulcrum effort output. Hockey stick, fishing pole, baseball. Increase distance but not direction
Fulcrum
Pivot point. Fixed point that a lever pivots around
Wheel & axle
Two circular or cylinder objects. Axel is the smaller radius object. Car’s wheel and doorknob. Increases force.
Pulley
Simple machine made of a grooved wheel with a rope wrapped around it. Rotating about a common axis. Can decrease force needed to lift it and it can change direction
Energy
Ability to do work
Kinetic energy
Energy and object has due to its motion
Potential energy
Stored energy that results from the position or shape of an object
Nonrenewable
Energy that cannot be used again
Fossil fuels
Renewable
Energy that can be of use again
Anything organic : wind energy, solar, water
Solar energy
Energy we get from the sun
Geothermal energy
Energy obtained from under the hot earth
Biomass
Energy from waste from plant or animals (decaying biological material
Unit for mass
Kg (g for density)
Unit for time
Seconds
Unit for acceleration
M/s^2
Unit for velocity/speed
M/s
Unit for force
N
Unit for momentum
Kg • m/s
Unit for density
Grams/mL or g/cm^3 (mass over volume)
Unit for pressure
Pa
Unit for work
J
Unit for power
W
Unit for distance
meters
What affects the strength of gravity
Mass and distance
How is mass related to an object’s inertia?
More mass=more inertia.
