What is a scalar?
A scalar is any quantity in physics to do with magnitude and is a normal integer
What is a vector?
This is any quantity in physics that has a magnitude and direction. Usually drawn with an arrow above the symbol to show the direction and magnitude
Examples of Scalars
Density Displacement Potential difference Power Temperature Wavelength Frequency
Examples or Vectors
Magnetic field Pressure Velocity Acceleration Force Current Momentum
What is a force?
- a force can change the shape of an object and state of rest of its motion
- measured in Newtons
- when the forces are balanced the result force is balanced (equal)
What happens when a stationary object moves?
- this is because of the resultant force
- it will have a certain direction depending on the speed of the object (speeds up and down)
3 Newton mechanical forces law
1)
- No force acting on object it will stay at rest
- Object moving at steady speed in a straight line, continue the same
2) A force applied to an object will change it’s speed in the same direction. Called acceleration depending on Newtons applies
3) For each force applied, the same amount of force will act in s different direction
Moment
- weight of the object (load)
- opposite weight is called the (effort)
- line force acts along (line of action)
- using a effort the effort needed to lift the same object is only a small fraction of it’s weight
2 Moment formulas
Moments= force x distance
F1 x D1= F2 x D2
What are gears?
- like levers as they multiply the effect of the engines forces
- bigger turning gap on a lower gear
- turning effect of the wheel shaft is bigger than the turning effect of it’s engine shaft
Low gear
- a small gear wheel driven by the engine shaft is used to turn a larger gear wheel on the output shaft
- output shaft turns slower than the input shaft
- low gear guides low speed and high turning effect
High gear
- an output shaft turns faster than the engine shaft
- turning effect of the output shaft is less than the turning effect of the engine shaft
- high gear gives high speeds and low turning effect
Gear Formula
Moment= force x gear wheel radius
Centre of mass
- in different objects there is a point within it that is considered the centre
- the mass of the object may be considered to act at a single point
Description of terminal velocity graph for parachutist
- as he jumps speed increases, with no air resistance
- accelerates towards earth with air resistance
- reaches a terminal velocity (constant speed)
- as opens parachute a lot of air resistance (decelerating)
- continues to decelerate
- reaches terminal velocity
What is momentum
- objects tendency to move in the same direction
- difficult to change direction of an object with high momentum
Two formulas for momentum
- Mass (kg) x Velocity (m/s)
- m1v1=m1v1
