part 2

• vector quantities include velocity momentum acceleration displacement force and weight
• speed does not involve direction
• speed is a scalar quality
• speed is a scalar quantity
• is speed vector or scalar

  scalar
• walking speed

  1.5 m/s
• running speed

  3 m/s
• cycling speed

  6 m/s
• what can affect the speeds

  age , terrain , fitness and distance travelled
• car

  30 m/s
• plane

  250 m/s
• train

  50 m/s
• velocity is speed in a given direction
• velocity is a vector
• when something moves in a circle its direction is changing constantly
• when something moves in a circle the speed stays the same but the velocity is always changing
• what is the centripetal force

  the force needed for circular motion which acts in the center of the circle
• all objects moving in a circle re always accelerating towards the center of the circle
• acceleration = change in velocity / time taken
• (final velocity) 2 − (initial velocity) 2 = 2 × acceleration × distance
• if the resultant force on an object is zero and ...

  the object is still , it stays still
• if the resultant force acting on an object is zero and

  the object is moving then it will still move at the same speed in the same direction
• the velocity of an object will only change if a resultant force acts on the object
• what is inertia

  the tendency of objects to continue in their state of rest or uniform motion
• newtons second law

  the acceleration is directly proportional to the resultant force and inversely proportional to the mass
• resultant force = mass x acceleration
• what is inertial mass

  how difficult it is the change an objects velocity
• newtons third law

  when two objects interact the forces they exert on each other are equal and opposite
• pressure = force / surface area
• pressure = height of column x liquid density x gravitational field strength
• breaking distance is the distance traveled after breaks are hit