Physics - AS Level - Motion
Terms
undefined, object
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- v =
- v = u + at
- x =
- x = ut + 1/2(at^2)
- u =
- initial velocity
- a =
- acceleration
- t =
- time
- v^2 =
- v^2 = u^2 + 2ax
- average velocity =
- x/t = (v+u)/2
- Acceleration of freefall, at this latitude:
- 9.81 m s^-2
- Newton's first law:
- 'Every object remains at rest or continues with constant velocity unless acted upon by a resultant force.'
- gravitational field strength at sea level:
- 9.81 N kg^-1
- Mathematical version of Newton's Second law:
- F = ma (F = resultant force (if a forward and back force, take back from forward to get resultant.))
- Free-body force diagram:
- shows all the forces acting on the object whose motion is to be analysed.
- momentum equation
- momentum = mass x velocity (p = mv). Momentum is a vector quantity.
- Newton's Second law:
-
The momentum change per unit time of an object is equal to the resultant force acting on that object.
rate of change of momentum = resultant force - Newtons second law formula:
- F = (delta(mv))/(delta t)
- impulse =
- force x time for which the force acts (newton's second law rearranged to F deltat = delta(mv))
- force vs time graphs - full area under curve =
- total momentum change of the ball = total impulse applied to the ball
- PCM
- The PRINCIPLE OF CONSERVATION OF MOMENTUM: 'If no external force acts on a system, then the total momentum of the system remains constant.'
- Newton's Third Law:
- 'If body A exerts a foce on body B, the B exert an equal but opposite force on A'
- The first force:
- 1. Gravity. The dominant force in the universe for shaping the large scale structure of galaxies and stars.
- The second force:
- 2. The strong nuclear force: Holds neutrons and protons together inside the nucleus.
- The third force:
- 3. The weak nuclear force: Involved in radioactivity.
- The fourth force:
-
4. The Electromagnetic force: Responsible for attractive and repulsive forces between atoms and is involved in each of the following:
i) Air resistance
ii) Contact forces
iii) Friction - The kinematic equations for a body moving in a straight line with uniform acceleration are: (4)
-
v = u + at
s = ut + 1/2(at^2)
v^2 = u^2 + 2as
v with line over = (u+v)/2 - The gradient of a displacement-time graph gives...
- the velocity of a particle
-
the gradient of a velocity-time graph gives...
the area between a velocity-time grpah and the time axis gives... -
the acceleration of a particle.
the displacement. - How is the motion of projectiles analysed?
- In terms of two independant motions at right angles. Horizontal component = constant velocity. Vertical is subject to constant acceleration