# force and motion

Term Definition
acceleration equals the change in velocity divided by the time for the change to take place; occurs when an object speeds up, slow downs or turns
momentum a measure of how difficult it is to stop a moving object ; equals the product of mass and velocity
speed equals the distance traveled divided by the time it takes to travel that distance
velocity speed and direction of a moving object
newtons first law of motion states that if the net force acting on object is zero the object will remain at rest or move in a straight line with a constant speed
newtons second law of motion states that an object acted upon by a net force will accelerate in the direction of the force and that the acceleration equals net force divided by the objects mass
newtons thrid law of motion states that forces always act equal but opposite pairs
friction force that acts to oppose sliding between two surfaces that are touching
unbalanced forces two or more forces acting on an object that do not cancel and cause the object to accelerate