P3.1&3.2

Displacement

Distance travelled from a given starting point in a particular direction

Instantaneous speed

Speed at a given moment

Average speed

Mean speed over a given time period

Velocity

Rate of change of displacement (Speed in a given direction)

Acceleration

Rate of change of velocity

Displacment-Time graph

Gradient=velocity

Velocity-Time graph

Gradient=acceleration Area under graph=displacement

SUVAT

S=displacement, U=initial velocity, V=final velocity, A=acceleration and T=time

Free fall

g=free fall=accleration due to gravity=9.81

Reaction time, hinking distance, breaking distance and stopping distance

Reaction time time for driver to act on breaking, thinking distance distance travelled by object whilst driver realieses whats happening, Breaking distance distance car decelerates for and stopping distnce sum of all.

F=ma

F=force (newtons) m=mass (kg) a=acceleration(m/s2)

W=mg

W=weight (newtons), m=mass (kg), g=9.81 (m/s2)

Tension

Force on a medium like a rope equal at both ends

Normal contact force

Equal and opposite force exerted on an object at rest perpendicular from object it is on

Friction

Force opposing motion

Upthrust

Upward force exerted on an object partially or completely submerged in a liquid.

Drag

Force opposing movement due to being in a fluid like air or water. Proportional to speed and changes due to shape of the object.

Terminal velocity

Maximum speed an object can reach when speed and drag are in equilibrium.

Moment of force

Force*perpendicular distance from pivot to the line of action of the force

Principle of moments

For a body to be in equilibrium the sum of clockwise moments about a point must = sum of anticlockwise moments

Couple

Paralelle forces of qual size which act in opposite directions produces turning force

Torque of a couple

size of one force*perpendicular distance between forces.

Density formula

p = m/v p=denisty, m=mass and v=volume

Pressure formula

p=f/a p=pressure, f=force and a=area

Upthrust in a fluid/Archimemeds principle

p=hpg p=pressure, h=height, p=denisty and g=9.81