phyics

• sound travels through solids, liquids or gases
• light travels at 300,000km/second
• newtons third law- force arises from the interaction between two objects
• newtens third law- forces come in a pair if they are equal size and the energy is the same
• friction- two objects slide over eachother (contact)
• magnetic - occurs when magnetic objects enter the field of a magnet (non contact)
• normal push force when objects are in contact with each other (keeps objects from sinking)
• electrostatic- non contact .bonds between positive and negative ions .
• gravity- pull force between two objects, changes dependent on size, distance between objects
• mass - the amount of matter in an object, measured in kilograms (kg)
• weight- the force of gravity acting on an object, measured in newtons (N) calculated by

  MASS kg x gravitational field strength
• scalar- measured on a scale
• distance - only measured on m
• speed = distance/time
• speed- distance travlled by an object over a period of time
• walking speed- 1-2 m/S
• cycling speed 5-6 m/s
• speed limit on uk moterway- 31 m/s
• speed of sound - 330 m/s
• speed of light - 3 x 10^8 m/s
• vector- identifies direction
• velocity- speed with direction
• stationary- stood still
• acceleration- time taken to change speed
• positive acceleration - right way

  negative acceleration- left way
• deceleration time taken to slow down
• acceleration change in speed/ time taken
• constant- same
• gradient - steepness
• diagonal line up - constant speed either slower or faster
• deceleration gragh- moving towards the start
• curved line- deceleration or acceleration
• to work out the total distance travelled from a velocity time gragh - work out area under line
• resultant- outcome of two forces (take away)
• if the forces are balanced and its already moving it will continue at constant speed.
• if its not moving the forces are balanced and the object is stationary
• if forces are unbalanced it can cause change in direction
• forces pulling upwards is called thrust
• there are always forces acting on objects
• objects which are falling through the air will experience air resistance. the larger the surface area of the object the more air resistance the slower the acceleration as it falls