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Chapter 3 Dynamics-explaining motion
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Gravity
Terms in this set (20)
Kinematics
A study of motion using quantities such as time, distance , displacement, speed, velocity, and acceleration.
Dynamics
A study of motion involving force and mass. Force=mass*acceleration
Newton's second law of motion
For a body of constant mass, its acceleration is directly proportional to the net force applied to it and take place in the direction of the resultant force. acceleration=force/mass and acceleration is proportional to mass.
Mass
It is a scalar quantity (Kg) and is a measure of a body's resistance to change in velocity ( Newton's laws applied). It is a measure of the amount of matter within a object and unless travelling at speeds close to the speed of light, mass is constant and does not depend on any gravitational force.
Inertia
The resistance of any physical object to any change in its state of motion (this includes changes to its speed, direction or state of rest). It is the tendency of objects to keep moving in a straight line at constant velocity. A massive object has a large inertia and a small object has less inertia.
Base units
Any of the fundamental units of length, mass, time, electric current, thermodynamic temperature, amount of substance, or luminous intensity in the International System of Units, consisting respectively of the meter, kilogram, second, ampere, kelvin, mole, and candela.
Derived units
Units that are a combination of the base units. meter/per second
Newtons
A unit of force and is a vector quantity. One newton is the force that will give a 1 kg mass an acceleration of 1 ms^-2 in the direction of the force. 1 N= 1kgms^-2
Homogeneous
When each term in an equation has the same base unit in the equation. A homogeneous material or system has the same properties at every point. It is uniform without irregularities.
Weight
The force on an object caused by a gravitational field acting on it mass ( weight = mass*acceleration in free fall. )
Center of gravity
The point where the entire weight of an object appears to act.
Uniform motion
Motion of an object travelling with a constant acceleration.
Newton's first law of motion
An object will remain at rest or in a state of uniform motion unless it is acted on by a net external force.
Resultant force
The net force acting on an object from a single vector that is equivalent to two or more vectors, automatically implies direction as well as magnitude.
Terminal velocity
The constant velocity of an object travelling through fluid (most commonly air). When drag is equal to weight, there is no net external force on the object and the vertical acceleration goes to zero. With no acceleration, the object falls at a constant velocity. Note when in free fall the air resistance at terminal velocity is equal to the weight.
Viscous force
Force that act on a body moving through a fluid that caused by resistance of the fluid, like air resistance.
Drag
A force that resist movement of a body through a fluid (most commonly air).
Contact force
The force an object exerts on another while it is in contact.
Upthrust
The upward force that a liquid exerts on a body floating or immersed in a liquid.
Newton's third law of motion
When two bodies interact, the force they exert on each other are equal in magnitude and opposite in direction.
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