what is a force?
Any push or pull taht happens when two objects interact
what are the two main forces
contact(two objects need to be touching) and non contact(two objects dont need to be touching)
what can forces do?
make objects change direction, speed and shape, and sometimes more than one
what is the unit and things we measure forces in?
we measure in newtons (N), and we measure it with spring balances and scales
what do you need to do when describing a force?
say what is pushing/pulling what, and any changes to speed direction and shape
What is a balanced force?
when an objects net force is exactly 0N. it wont change speed direction and shape
What is an unbalanced force?
when an objects net force is more than 0N. it will change speed direction and shape
what is friction?
the force that resists movement between two objects that’re touching (contact force)
what does the amount of friction depend on?
the weight of object (more weight=more friction) and smoothness of surface (more rough, more friction)
how is levitation used?
levitation reduces or removes contact between two objects, which reduces or removes friction
how is rollers/balls used?
rollers and balls roll along surfaces, which produce much less friction than dragging
how is streamlining used?
making an object streamlined (smooth and rounded) helps decrease friction between the object and air (or water)
how is lubrication used??
using a lubricant such as oil or grease makes surfaces slippery, reducing friction
