Forces and energy Flashcards
stopping distance formula
thinking distance + braking distance
thinking distance definition
distance travelled during drivers reaction time
thinking distance factors
speed of car
drivers tiredness
influence of alcohol or other drugs
distractions/lack of concentration
braking distance factors
speed of car road conditions tyre conditions brake conditions mass of car
Newton’s 1st Law
objects will remain at rest or at uniform motion unless compelled to change its state by action of an external force
Newton’s 2nd Law
acceleration is always cause by a resultant force
Newton’s 2nd law formula
force (N) = mass (kg) x acceleration (ms^-2)
F = m x a
friction definition
force that opposes motion and acts to slow down moving objects
types of friction
static friction (stationary object and surface it is on gripping) sliding friction (between objects that slide against each other) fluid friction (between solid objects and fluid)
friction factors
increases with speed
objects shape, area
Newton’s 3rd law
when 2 objects interact, they exert forces in each other equal in magnitude and opposite in direction
work done definition
energy transferred to an object
work done formula
work done (J) = force (N) x distance moved in direction of force (m) W = F x d
gravitational field strength of earth
10N/kg
weight formula
weight (N) = mass (kg) x gravitational field strength (N/kg)
W = mg
