1.
The rate of change of position along a straight line with respect to time : the derivative of position with respect to time.
2.
The rate of change of velocity with respect to time broadly : change of velocity.
3.
A property (see property sense 1a) of a moving body that the body has by virtue of its mass (see mass entry 2 sense 1c) and motion and that is equal to the product of the body's mass and velocity.
4.
The condition of unrestrained motion in a gravitational field also : such motion.
5.
A fundamental physical force that is responsible for interactions which occur because of mass between particles, between aggregations of matter (such as stars and planets), and between particles (such as photons) and aggregations of matter, that is 10-39
6.
The force that is necessary to keep an object moving in a curved path and that is directed inward toward the center of rotation.
7.
Means that an object's state of motion will not change unless an external force acts upon it. It is also known as the law of inertia.
8.
States that the acceleration of an object depends upon two variables – the net force acting on the object and the mass of the object.
9.
Means that for every force (action) there is an equal and opposite reaction.
10.
The force that resists relative motion between two bodies in contact.
11.
Acts between objects at rest, preventing them from starting to move.
12.
Acts on objects that are sliding over a surface and is generally less than static friction.
13.
Acts on objects as they roll over a surface and is significantly weaker than sliding friction.
14.
(Also known as drag) acts on objects moving through a liquid or gas and depends on factors like speed and viscosity.
15.
Is a force that opposes the motion of an object through the air. It is a form of friction caused by an object colliding with air molecules. This force acts in the opposite direction of the object's velocity, slowing it down.
16.
A property of matter by which it remains at rest or in uniform motion in the same straight line unless acted upon by some external force.
17.
A quantity or aggregate of matter usually of considerable size.
18.
The force with which a body is attracted toward the earth or a celestial body by gravitation and which is equal to the product of the mass and the local gravitational acceleration.
19.
Strength or energy exerted or brought to bear : cause of motion or change : active power.
20.
Is a force that is opposed by an equal force in the opposite direction.
21.
Is a net force acting on an object that changes its state of motion.
22.
Forces acting in opposite directions. These forces are central to the concepts of balanced forces (leading to no change in motion) and unbalanced forces (causing acceleration).
