Lecture 8 - Visualizing Forces Flashcards
- do practice math questions!
1
Q
what is a force?
A
- an action that causes mass to be accelerated
2
Q
what are Isaac Newton’s 3 Laws?
A
- objects don’t want to be accelerated because they possess inertia
- the force required to accelerate an object is proportional to it’s mass (F = m x a)
- if a force is applied to an object, the object pushes back with the same force
3
Q
what is the law of inertia?
A
- mass doesn’t want to be accelerated
- if staying still wants to remain still
- if moving, wants to remain moving at that speed
4
Q
what is the law of force?
A
- m is a scalar
- acceleration and force go in the same direction
- amount of force needed can be determined by acceleration x mass
5
Q
what is the law of action/reaction?
A
- amount of force put into an object is returned (proportional)
- heavy objects return more force (painful)
- light object return less force (which is why they move)
- the ball doesn’t care what the foot is doing and vice versa (force acts on different objects which causes movement)
6
Q
what is the property of mass?
A
- magnitude (measured in kg)
- only 1 because scalar
- amount of matter that makes up an object
7
Q
what is the difference between mass and weight?
A
- mass is scalar, weight is a force (because of gravity)
- astronauts have the same mass in space but their weight is different
8
Q
what are the properties of weight?
A
- a force (gravity)
- measured in newtons (N) or lbs
9
Q
what are the 4 properties of a force?
A
- force is a vector
1. has a magnitude
2. has a direction
3. has a point of application (where force is being applied)
4. has a line of action (where force has been and where it is going)
10
Q
what is the center of mass?
A
- point of application of gravity
- aka center of gravity
- doesn’t have to be within the object
- can move around as body moves and weight is redistributed
11
Q
when might it be useful to put the center of mass outside of the body?
A
- lower center of mass = less force required
- for example: with high jump (fosbury flop)
12
Q
what are the components of force?
A
- resultant force = the line of force an object has (made up of horizontal and downward forces)
- angle of push = angle between horizontal and downward force you are pushing at (Pythagorean theorem)
13
Q
what are non-orthogonal forces?
A
- means the input forces are not at 90 degrees from each other
- us F1 and F2 (instead of horizontal and downwards)
14
Q
what is collinear force?
A
- all lines of action are parallel
- moving straight up while holding a weight for example
15
Q
what are the steps to draw a resultant force graphically?
A
- draw the line of push (from POA)
- draw a horizontal direction (from POA)
- draw a vertical direction (from POA)
- complete the rectangle