KINETICS - forces and moments of force

Question 1

what is kinetics

Answer 1

study of motion and its cause
-indicate why and how motion is occurring

Question 2

according to newtons 2nd law, whenever an object accelerates there must be what and what is this in math equation

Answer 2

a non-zero resultant force acting on the object that is proportional to the acceleration and in the same direction
R = sum of forces = ma

Question 3

what happens to the magnitude of velocity if the net external force and velocity are in the same direction

Answer 3

increases

Question 4

what happens to the magnitude of velocity of the net external force and velocity are in the opposite direction

Answer 4

decreases

Question 5

what happens to the magnitude of velocity if velocity and force are both in the positive direction and what happens if they are both in the negative direction

Answer 5

POSITIVE
-increase in the positive direction
NEGATIVE
-increase in the negative direction

Question 6

what happens to the magnitude of velocity if velocity is in the positive direction and force is in the negative

Answer 6

decrease in the positive direction

Question 7

what happens to the magnitude of velocity of velocity is in the negative direction and force is in the positive

Answer 7

decrease in the negative direction

Question 8

What is inverse dynamics

Answer 8

indirect
-calculating kinetic info from measured kinetic info (displacements, velocities, acceleration)
-external forces

Question 9

what is direct dynamics

Answer 9

deals with how an object will move knowing the forces acting on it
-calculating the kinematics of objects given knowledge of the mechanisms causing force

Question 10

how to create angular motion

Answer 10

force must be applied to an object in a way that the forces lone of action does NOT pass through the objects CoM
-either a eccentric or concurrent force not a centric force

Question 11

what is moment of inertia

Answer 11

resistance of a body to a change in its state of rotational motion
-change in angular velocity and therefor angular acceleration

Question 12

moment of intertia determines the amount of force required to what

Answer 12

attain an angular acceleration about an axis

Question 13

moment of inertia can be considered the rotational equivalent to what

Answer 13

mass
-mass of an object determines the force required to accelerate an object (linear)