1A Motion Flashcards
Average speed
The total distance of a journey divided by the total time
Instantaneous speed
The speed at one particular moment in time
Vector
Has a magnitude and a direction
Scalar
Doesn’t have a direction
Distance
how far an object has moved in total
Displacement
how far and in which direction an object is from its initial position
Speed
the rate of change of distance
Velocity
the rate of change of displacement
Acceleration
the rate of change of velocity
Forces type
- Weight (gravity)
- Static electric force
- Magnetic force
- Thrust
- Friction
- Air resistance (viscous drag)
- Upthrust
- Normal force
Thrust
Due to engines and objects propelling themselves
Upthrust
- Acts on objects in fluids
- Equal to weight of displaced fluid
- Usually negligible - unless object density less than surrounding medium
Normal or contact force
- The force that stops solids moving through each
other - Acts whenever two surfaces are in contact
- Acts perpendicular (90 degrees) to surface
- Stops objects moving through each other
Friction
- Happens when touching objects move
- Always acts opposite direction to movement
Air resistance
- Opposes objects moving through fluids
- Depends on shape, but not mass
- Increases with speed
newton’s first law
A body at rest remains at rest or, if in motion, remains in motion at constant velocity unless acted on by a non-zero resultant force
newton’s second law
- The resultant force on an object is proportional to the mass times the acceleration the object experiences.
- The acceleration of an object is
directly proportional to the resultant force on it
and indirectly proportional to its mass
newton’s third law
When an object exerts a force on another object, the second object exerts an equal and opposite force on the first.
Work done is the same as…
Energy transfered
If you hold something…
you are not doing work, you are tranfering energy withing your body
If you lift something…
you are doing work
conservation of energy
energy is conserved the decrease in GPE = increase in KE, for a falling object if no energy is lost to the surroundings
Power =
Force x Velocity
Mass
How much matter there is in an object (it doesnt change)
