Ch. 12 vocab Flashcards
What is an SI unit that measures a force?
newton
What is a push or pull that acts over an object?
force
What is the overall force acting on an object after all the forces are combined?
net force
What is a force that opposes the motion of objects that touch as they move past each other ?
friction
What is the friction force that acts on objects that are not moving?
static friction
What is a force that opposes the direction of motion of an object as it slides over a surface?
sliding friction
What is a change in shape at the point of rolling contact?
rolling friction
What is a force that opposes the motion of an object through a fluid?
fluid friction
What is it called when fluid friction acts on an object moving through the air?
Air resistance
What is a force that acts between any two masses?
gravity
What is the constant velocity of a falling object when the force of air resistance equals the force of gravity?
terminal velocity
What is the motion of a falling object after it is given an initial forward velocity?
projectile motion
Who was an ancient Greek scientist and philosopher who incorrectly proposed that a force is required to keep an object moving at a constant?
Aristotle
Who was an Italian scientist who concluded that moving objects not subjected to friction or an other force would continue to move indefinitely?
Galileo
Who was the first person to define mass and mass and force?
Newton
How can a force accelerate a moving object?
by changing its speed and direction
A newton causes a 1km mass to accelerate to what?
1 km/s2
If forces are moving in the same direction, you ______ the forces.
add
If forces are moving in the opposite direction, you _________ the forces.
subtract
If the net force is ____, then there is no motion.
0
When an unbalanced force acts on an object, there is _________.
motion
All moving objects are subject to ________.
friction
List the order of the four frictions in order from weakest to strongest.
fluid friction,
rolling friction,
sliding friction,
static friction
A _______ force balances out a downwards force of gravity.
upward
_________ causes objects to accelerate downwards, whereas ___ __________ acts in the direction opposite to the motion and reduces acceleration.
gravity,
air resistance
State Newtons 1st law of motion.
An object at rest tends to stay at rest, while an object in motion tends to stay in motion unless acted upon by an unbalanced force
What is Newton’s first law of motion also known as?
law of inertia
State Newton’s second law of motion.
Acceleration is directly proportional to the size of the force
Acceleration is inversely proportional to mass
A=f/m
State Newton’s third law of motion.
For every action, there is an equal but opposite reaction
