two or more forces exerted on an object cancel each other out and do not change the object's velocity
two or more forces exerted on an object do not cancel each other out so the objects velocity changes
Newton's first law of motion
if the net force on an object is zero, the object at rest stays at rest, while the object in motion stays in motion
Newton's second law of motion
the acceleration of an object equals the net force divided by the mass and is in the direction of the net force
center of mass
the point in an object that moves as if all the object's mass were concentrated at that point
a force that opposes the motion that occurs when one solid surface slides over another
the friction that prevents an object from moving when a force is applied is __________ friction
The speed an object reaches when the force of gravity is balanced by the fore of air resistance is called ____________________.
Newton's__________ law of motion describes the connection between an object supplying force and the object receiving the force.
A force in the opposite direction to the motion of the object will cause the object to ____________
Why is it easy to miss an action reaction pair?
It is easy to miss an action reaction pair because one of the objects is often more massive and appears to be motionless
Why does friction never speed up an object?
If 2 objects are in contact, frictional forces always try to prevent one object from sliding on the other.
One reason it's often easy to miss an action reaction pair is b/c of the _____________ of one of the objects
Action reaction forces are always the same _________ but are in opposite ___________
The ______________ is reached when the force of gravity; the size of the air resistance depends on the shape of an object and its speed
An object can speed up, slow down or turn in the direction of the net force when the __________ forces act on it.
Galileo realized that an object could be in motion if the ________ acting on it were _____________. In real life, _____________ is the force that ________ _____objects down and causes them to ________. Newton's _________ law of motion described how forces cause the motion of objects to _________: An object at rest remains at rest and an object in motion continues to move in a ___________ line with constant _________if the net force action on it is _____.