Zusammenfassung der Ressource
Forces
- Forces and work done
- Scalar
- Speed
- Distance
- Overall
- Vector
- Velocity
- Displacement
- In a certain direction
- Contact forces touch the object
- Non-contact can act without
touching the object, e.g. gravity
- Resultant force diagrams
- If forces cancel out, the object doesn't move
- W.D = force * distance
- Stretching and turning
- Deformations
- An elastic deformation is one
which returns to its origional shape
- An inelastic one is one that
doesn't return to its original shape
- The spring constant is k
when force = k*extention
- found in force-extension graphs by the gradient
- Are under the graph = elastic energy stored
- Moments
- Moment of a force = force * distance
- Bigger distance = bigger force
- for an object to balance, the clockwise and
anticlockwise moments must be the same
- Gears rotation changes for each gear connected
- Pressure
- pressure = force / area
- measured in pascals
- Pressure increases the deeper you are in a
liquid as there is more liquid on top of you
- Pressure(pa) = depth(m) * density(kg/m^3)
* gravitational field strength(N/kg)
- Upthrust occurs when the pressure at the bottom
of an object is greater than the pressure at the top
- Atmospheric pressure decreases with height
- Motion
- displacement is the distance from
one point to another in one direction
- distance is how far something has traveled
- Acceleration = velocity/time
- Uniform acceleration means accelerating at a constant rate
- The gradient of a distance-time graph = speed
- The gradient of a velocity-time graph = acceleration
- Terminal velocity is the speed at which the
deceleration from air resistance = acceleration
from gravity so an object stops accelerating
- Newtons laws
- An object needs a force to move
- Acceleration is directly proportional to resultant force
- each action has an equal and opposite reation
- Inertia is the tendency for an object's
motion to remain unchanged
- Car safety and momentum
- Stopping distance = thinking distance + braking distance
- reaction times
- factors
- speed (both the distance
over time and the drug)
- Reaction time
- tiredness
- drugs
- alcohol
- average reaction times
- Tests
- Drop a ruler unexpectedly
and see where they catch it
- Identify when colour changes
and how long it was since the
colour actually changed
- Breaking time factors
- Speed (not the drug this time)
- weather
- Tyre condition
- How good the brakes are
- Momentum is vector
- Cars are designed to stop a person over a
longer period of time to make the force lower