Forces Motion And Electricity Flashcards
Unit of speed and velocity
M/s
Speed is…
Velocity is…
Speed is how fast you are going
Velocity is the same but the direction is also specified
Acceleration =
Change in velocity/tine
What is acceleration
How quickly the velocity is changing
Distance time graphs
Gradient = speed Steeper is faster Flat is where stopped Downhill is going back to starting point Curves are accel or deccel
Velocity time graphs
Gradient = acceleration
Flat is steady speed
Steeper is greater accel or deccel
Curve is changing acceleration
Weight =
mass x gravitational field strength
Terminal velocity
A final speed you hit when falling, it is related to its weight and drag
First law of motion
Balanced forces mean no change in velocity
Second law of motion
If there is an unbalanced force than the object will accelerate in that direction
Another word for this is the resultant force
Third law of motion
Reaction forces
If you push on something it pushes back and the smallest mass is accelerated further
Resultant force =
F
Mass x acceleration
Stopping distance =
Whole time to stop
Braking distance + thinking distance
Thinking distance
And factors
Distance car travels for driver to react and apply brakes
Speed
Reaction time/state (tired or drunk)
Braking distance
And factors
The distance car travels during brakes on to stop
Speed
Mass of vehicle and people inside
State of brakes
Grip - road weather. Tyres.
Momentum =
(P)
Kg m/s
Mass x velocity
Momentum before =
Momentum after
Force =
Change in momentum/time taken for change to happen
Crumples zones
Crumple on impact to increase the time taken for a car to stop
Seat belts
Stretch slightly to increase the time taken for a wearer to stop
Reduce force on chest
Air bags
Also slow you down more gradually
A moment is a
Turning effect of a force