Science Final Flashcards
On a speed time graph, a line with a negative slope indicates that the object is
Slowing down
The combination of all of the forces acting on an object is called the
Net force
If the net force acting on a stationary object is zero, the object will
Remain at rest
Give an example of unbalanced forces acting on an object
Tug-of-war, with one team winning
Give an example of balanced forces acting on an object
A leaf lying on the grass
Name 3 ways to describe the force of friction
Lubricant, smooth surfaces, wheels
The SI unit for speed is?
M/s
Meters per second
Define static friction
Friction between stationary objects
In order to keep the car from rolling downhill, the static friction must be
Equal to the force pulling it down
An object that changes position relative to a reference point is
In motion
The equation for average speed is
V=d/t
What is the difference between speed and velocity?
Velocity is both speed and direction
What is the difference between distance traveled and displacement?
Displacement must always indicate direction
Define acceleration
Change in velocity or speed overtime, speeding up, slowing down, direction change
What is negative acceleration
Slowing down
What is positive acceleration
Speeding up
The SI unit for acceleration is
M/s squared
What is centripetal acceleration, what happens
An object changes directions
The equation for average acceleration of straight line motion is
A= ^v/t= vf-vi/t
Gravitational force depends on what 2 factors
Mass of objects + distance between them
Which one, if greater, increases gravitational force
Mass
Which one, if greater, decreases gravitational force
Distance
Define Newton’s first law of motion
Inertia, every object maintains Constant velocity unless acted on by unbalanced force
Define Newton’s second law of motion
F=ma
The force acting on an object equals The objects mass times acceleration
Define newtons 3rd law of motion
For every action force there is an equal+ opposite reaction force
Do action/reaction force pairs act on the same object
NO
Define the law of conservation of momentum
Momentum before crash equals momentum after crash
Define terminal velocity
When gravity + air resistance equalize on an object that is falling + the object stops accelerating
In the absence of air resistance, does mass affect downward acceleration
No
What is the acceleration due to gravity for all objects
9.8 m/s squared
Define inertia
Tendency of object to keep moving
Does mass affect inertia
Yes, more mass, greater inertia
1 Newton =
1 kg * m/s squared
If a equal force is applied to two objects, with equal masses, the acceleration will be
The same. F=ma
Does all matter exert A gravitational force
Yes
When an object is in freefall, the only force acting on it is
Gravity
Orbital motion is a combination of
Forward motion + free fall
What is the difference between weight and mass
Weight is a force of gravity on a given mass
How do we calculate weight on earth if given an objects mass
W=mg
How does an objects weight change if it is on the moon instead of earth?
Weighs less but has some Mass
Astronauts “float “ in an orbiting space ship because they are
In free fall
Give an example of projectile motion
Darts
Momentum=
Mass * velocity
Define work
The transfer of energy to a body application of a force that causes the body to move in the direction of the force
What is the formula for work
W=Fd
What are the units for work
Joules
Define power
Rate at which work is done
What is the formula for power
P=w/t
What are the units for power
Watts
Define energy
Ability or capacity to do work
What are the units for energy
Joules
What is the formula for gravitational potential?
Pe=mgh (g= 9.8 m/s squared)
Define the law of conservation of energy
Energy cannot be created or destroyed
The primary source of the suns energy is
Nuclear fusion
Define the law of thermodynamics
Total energy in any process is conserved
Define convection
Transfer of energy by movements of fluids or gases with different temperatures
Define conduction
Transfer of energy as heat caused by the collision of molecules
Define radiation
How it differs from convection+conduction does not involve the movement of matter
Temperature is a measure of
Average kinetic energy
What are the 3 most common temperature scales
K F C
Kelvin, Fahrenheit, Celsius
The Temperature at which all molecular motion stops is
Absolute zero
Define heat
Energy transferred between objects with different temperatures
Define specific heat
How much energy is required to raise an object temperature
Heat always moves from
Higher temperature to lower temperature
When energy is transformed, the amount of usable energy
Decreases
Give a example of a heat conductor
Iron metal
Give a example of a heat insulator
Foam
As kinetic energy increases, temperature
Increases
Convection currents rise in air because
Hot air rises, cold air sinks
Feeling the sensation of warmth is a result of the transfer of
Energy (as heat)
Electric current that periodically reverses its direction
Alternating current
What is the advantage of using a parallel circuit instead of a series circuit
Parallel has multiple paths for a current
Two positive charges will —– One another. A positive and a negative charge will —— one another
Repel, attract
What does it mean if a circuit is open? Closed?
Open, electrons cannot flow. Closed, electrons can flow
A material which opposes the flow of electrons and slows current
Resister
The rate at which charges move through an electrical conductor
Current
The potential difference that essentially “pushes “electrons through a circuit
Voltage
Electrons always move from
Negative to positive
