Question | Answer |
motion | an objects change in position relative to a reference point |
speed | the distance traveled by an object divided by the time taken to travel the distance |
velosity | the speed of an object in a particular direction. must include reference direction*velosity changes if speed or direction changes* |
acceleration | the rate at which velocity changes. object accelerates if its speed direction or both change |
forces | a push or pull on an object. newtons (N) |
net force | the combination of all the forces acting on an object |
balanced forces | when the forces on an object produce a net force of 0n |
unbalanced forces | when the net force on an object is not 0n |
friction | a force that opposes motion between two surfaces that are in contact |
greater the force = | greater the friction |
rougher the surface = | greater the friction |
kinetic friction = | moving friction |
what are two types of kinetic friction? | sliding and rolling friction |
static friction | not moving friction |
ways to reduce friction | adding lubricants (oil or wax) switching from sliding to rolling friction making the surfaces smoother |
ways to increase friction | make the surface rougher or to increase force |
gravity | a force of attraction between objects that is due to their masses |
all matter is affected by what? | gravity, all objects experience an attraction towards other objects (depends on mass) |
force must be applied to overcome what? | to overcome gravitational force |
newtons law of universal gravitation | all objects in the universe attract each other through gravitational force, the size of force depends on the mass and the distance between the objects |
part 1 | gravitational force increases as mass increases |
part 2 | gravitational force decreases as distance increases |
weight | a measure of gravitational force on an object |
mass | the amount of matter in an object |