Exam 1: Chapter 2 Flashcards
(39 cards)
What is general motion?
It involves a combination of translational (linear) and rotational (angular) movement simultaneously. Most human movement is general motion.
Describe Linear Motion.
Movement along a line that may be straight or curved, with all parts of the body moving in the same direction at the same speed.
-Ex: A sleeping passenger on a smooth airplane flight is being translated through the air.
Describe Angular Motion.
Movement involving rotation around a central line or point.
-Ex: A gymnast performing a giant circle on a bar, the entire body rotates, with the axis of rotation passing through the center of the bar.
What are two other names for linear motion?
Translatory motion or translational motion.
What are the two subcategories within linear motion?
Rectilinear Motion - along a straight line
-Ex: A motorcyclist maintaining a motionless posture as the bike moves along a straight path.
Curvilinear Motion - along a curved line
-Ex: A skier going over the crest of a hill, the motion is not linear because the top of the body is moving at a greater speed than lower body parts.
Here are some examples of general motion (a combination of both)
Ex: A football kicked end over end translates through the air as it simultaneously rotates around a central axis.
Ex: A runner is translated along by angular movements of body segments at the hip, knee, and ankle.
What is one tool used to determine the position of an object or body?
Cartesian System
What is distance?
The total amount of length traveled from A to B.
What is displacement?
Strictly the length from A to B.
What is speed?
Speed is the rate of motion.
What is velocity?
Velocity is the rate of motion in a specific direction.
Compare and contrast average speed and instantaneous speed.
Average speed - occurring over a designated time interval, the overall speed over a period
Instantaneous speed - occurring during a small interval of time, the speed at that specific point in time.
Compare and contrast speed and velocity in terms of physics.
Speed - is a scalar quantity; it is defined as the distance covered divided by the time taken to cover it.
Velocity - is a vector quantity; it is defined as the change in position/displacement that occurs during a given period of time.
What is acceleration?
It is defined as the rate of change in velocity over a given time internal.
What happens when acceleration is zero?
Your velocity will remain constant.
What does a positive acceleration value mean.
It can mean that you are speeding up OR down. It depends on the position.
What is projectile motion?
It refers to objects moving in the air.
What’s the only thing that can influence the path of a projectile?
Gravity (and air resistance, but we neglect that)
What is a projectile?
A body in free fall that is ONLY subjected to the forces of gravity and air resistance.
Describe the influences of the vertical and horizontal components of a projectile.
The vertical component is always influenced by gravity, whereas no force affects the horizontal component.
Once a body or object has been projected into the air, what is constantly changing?
Its overall resultant velocity is constantly changing because of the forces acting on it.
What remains constant for a projectile in motion, regardless of its size, shape, and weight.
The accelerative force of gravity towards the surface of the earth.
What is the apex?
It is the highest point in the trajectory of a projectile.
What can you say about the initial and final speed of an object that is thrown and caught at the same height?
If the object is caught at the same height from which it was tossed, the ball’s speed is exactly the same as its initial speed, although its direction is now reversed.
