Vectors
describe forces in size or magnitude and direction
length = magnitude shaft = line of action and point of application arrowhead = direction
Internal Forces
- act within the object or system to change shape
- incapable of producing changes in COM (center of mass)
- muscles
External Forces
- occur as a result of interaction with environment
- capable of producing changes in COM (center of mass)
- non-contact and contact forces
Non-Contact Forces
Gravitational Force
weight (N) = mass * gravity
Contact Forces
Normal Contact Forces
- normal reaction force
- perpendicular to surfaces
Friction
- parallel to surfaces
- opposes motion (occurs in opposite direction of motion)
*normal contact forces and friction inc. due to inc. in weight & in molecular interactions btwn contact surfaces
Force Composition
takes several external forces and puts them together to figure out the resolution
result of forces combining
“resultant vector” or “..force”
Force Resolution
takes the result & breaks them down into the individual forces
breaking resultant vector into its horizontal and vertical components
Resultant Vector
result of vector addition of forces
represented by a resultant vector
Colinear Forces
forces that have the same line of action
- forces are on the same line or plane at the same time but don’t have to go in the same direction
- tip to tail
Resultant Force
found by drawing an arrow from the tail of the first force to the top of the last force
It is calculated by summing the forces
ex. tug of war
Concurrent Forces
forces that occur at the same time but do not act on the same line, but they do act through the same point
Pythagorean theorem
A2 + B2 = C2
