Kinematics Flashcards
Kinematics
Motion in one direction
The first two important things
- The object of interest
2. The person describing the object
Reference frame
All motion is relative
Inertial reference frame
No acceleration
Non-inertial reference frame
Acceleration
Is there an ideal reference frame?
No, there is no universal reference frame that is not moving.
What does “speed is a scalar” mean?
It has a magnitude but no direction.
What does “velocity is a vector” mean?
It has a magnitude and a direction.
Order of magnitude
Power of 10.
What is the physical meaning of the slope of a position vs. time graph?
The object’s velocity.
What is the physical meaning of the slope of a velocity vs. time graph?
The object’s acceleration.
Velocity =
Displacement/time
∆x/∆t
Acceleration =
∆v/∆t
Motion
A change in an object’s position relative to a given observer during a certain change in time.
Motion is relative
The motion of any object of interest depends on the point of view of the observer.
Components of a reference frame
An object of reference
A coordinate system
A clock
Time or clock reading t (a scalar quantity)
The reading on a clock or another time measuring instrument.
Time interval Δt (a scalar quantity)
The difference of two times.
Position x (a scalar quantity)
The location of an object relative to the chosen origin.
Displacement ⃗d
A vector drawn from the initial position of an object to its final position. The x-component of the displacement dx is the change in position of the object along the x-axis.
Distance d (a scalar quantity)
The magnitude of the displacement and is always positive.
Path length l
The length a string laid along the path the object took (total distance).
Velocity ⃗v (a vector quantity)
The displacement of an object during a time interval divided by that time interval. The velocity is instantaneous if the time interval is very small (approaches zero) and average if the time interval is longer.
Speed v (a scalar quantity)
The magnitude of the velocity.
