Zusammenfassung der Ressource
Force
- Newton's Laws
- Newton's first law states that every object will remain at rest or
in uniform motion in a straight line unless compelled to change
its state by the action of an external force (aka. inertia).
- The third law states that for every action (force)
in nature there is an equal and opposite reaction.
- The second law explains how the velocity of an object
changes when it is subjected to an external force.
- Formulas
- Speed = distance / time
- net Force = mass x acceleration
- Acceleration = v - u / time
- Pressure = force / area
- Density = mass / volume
- Weight = mass x gravitational acceleration
- (Hooke's Law) F = kx
- Work Done = force x distance
- Forces
- SCALAR VS VECTOR
- SCALAR quantities have magnitude only. (speed)
- VECTOR quantities have magnitude and an associated direction. (velocity)
- CONTACT VS NON CONTACT
- contact forces - the objects are physically touching
e.g. friction, air resistance or tention
- non-contact - the objects are physically separated
e.g. gravitational force, electrostatic force or
magnetic force
- RESULTANT FORCES
- resultant force = the total effect of all the
different forces acting on an object
- WORK DONE AND ENERGY TRANSFER
- work is done when a force causes an object to move. the force causes a displacement
- GRAVITY
- weight is the force acting on an object due to gravity
- all matter has a gravitational field that causes attraction. the
field strength is much greater for massive objects
- Elasticity
- SPRING CONSTANT
- stretching - when a spring is stretched, the
force pulling it exceeds the force of the spring
- bending - when a shelf bends under the weight of too many books, the downward
force is from the weight of the books, and the shelf is resisting this weight
- compressing - when a car goes over a bump in the road, the
force upwards is opposed by the springs in the car's suspension
- ELASTIC DEFORMATION
- Elastically deformed - stretched object that returns
to it's original length after the force is removed
- INELASTIC DEFORMATION
- Inelastically deformed - stretched object that does not
return to its original length after the force is removed
- Stopping Distance
- THINKING DISTANCE
- distance travelled before the driver applies the brakes
- BRAKING DISTANCE
- distance a vehicle travels after the brakes have been applied
- Displacement
- VELOCITY
- acceleration
- DISTANCE
- speed