Unit 1: Motion

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Terms in this set (...)

average speed
the distance traveled by an object divided by time it traveled

Therefore, to determine how far an object travels over a time period in which its speed is changing, it is often useful to determine the ? over a period of time.
power
the ratio of the amount of work done per unit of time, or the rate at which energy is transferred or transformed

The electric meter at your home tells how many kilowatts of ? is used.
momentum
a quantity of how much inertia a dynamic object has

The total ? in a closed system is constant. If the ? of an object changes it must have been acted upon by a force.
centripetal force
any force that causes centripetal acceleration

The tension is a ? causing the direction of the bob's path to change.
displacement (vector)
a length vector pointing from an object's starting point to its ending point

?, unlike distance, is concerned only with the difference between an object's starting and ending points.
scalar
a quantity that is measured by its magnitude (amount) but has no direction

Physical quantities such as mass, volume, density, and time, are examples of ?quantities.
energy
the ability to do work or cause change; can be stored in chemicals found in food and released to the organism to do work

our body constantly uses ?, which comes from the food you eat.
uniform circular motion
motion that is both circular and at constant speed

? implies that the motion takes place in a circular path and that the speed of the object is constant throughout the motion.
speed
the rate at which distance is traveled

? is a measure of how fast something is moving.
work
the change in a system's kinetic energy due to being acted on by a force

Work is a measure of how much energy is exerted on an object.
free body diagram
a diagram showing all the forces acting on an object

A (often abbreviated as FBD) is used to show all the forces acting on a single object.
acceleration due to gravity
the change in velocity caused by a gravitational force

the change in velocity due to this force is ?
force
an interaction between objects that causes a change to the objects' motion.

Thrust, lift, drag and weight are four aerodynamic ? that act on an aircraft in flight.
acceleration
a change in velocity over time

An object's velocity can increase, decrease, or change direction. These changes in velocity are described as ?
velocity
a vector quantity that indicates both the rate at which displacement changes and the direction of motion

Velocity is a vector formed by computing the displacement per unit time.
vector
Velocity is a vector formed by computing the displacement per unit time.

Scalar quantities measure only magnitude, but ? quantities measure both magnitude and direction.
center of gravity
the average location of the weight of a system

The ? is defined as that point in an extended body which moves in a gravitational field as if all the mass were concentrated at that one point.
center of mass
the average location of the mass of a system

The ? can be described as the average location of the mass of the object.
instantaneous velocity
the rate of motion of an object traveling in a specified direction at a point in time


If an object's ? is not constant, its average velocity will be be different from its ?
instantaneous speed
the rate of motion of an object at a point in time

The speedometer of a motor car provides a reading of the vehicle's ?
static friction
a resistive force between stationary objects due to the roughness of the two surfaces in contact

? is the type of friction that exists between two touching stationary objects.
frame of reference
an item against which the motion of an object can be measured

Motion might appear different from different ?
Newton's law of universal gravitation
the law that states that the magnitude of the gravitational force increases as the mass of the two objects increases and decreases as the distance between the objects increases

? states that when two objects interact, the gravitational force acts on both of them with equal strength but in opposite directions.
non-inertial frame of reference
coordinate system and set of points that depend on the location and orientation of objects in space and time

An outside observer is in a ? with respect to someone inside an elevator who does not experience motion because they are in the inertial frame of reference.
inertial frame of reference
coordinate system and set of points to independently locate and orient objects in space and time

The ? is a a key concept in general relativity.
Newton's laws
the three fundamental laws Isaac Newton discovered governing the motion of objects


One of ? states: "An object in motion stays in motion, unless acted on by a force. An object at rest stays at rest unless acted on by a force."
equilibrium
state of balance between all parts of a system

Objects in ? have no net force acting on them.
inertia
an object's resistance to a change in motion

In outer space, there is no atmosphere or friction. Satellites travel around the earth without stopping. This is because of ?
net force
the resulting force determined by combining all of the forces acting on an object

In the end, the ? on the ball will be positive in the direction that it is kicked, as it would be greater then the frictional force.

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