Unit 1: Motion Flashcards
(30 cards)
Define kinetics
The study of motion that can occur in linear (translation) or rotatory motion
What is the difference between SI units and derived units
SI units are the common units (e.g. metre) whereas derived units are formed by combining base units (e.g. the radian)
What is the relationship between degrees and radians
2 pi radians = 360 degrees
What is the equation for converting from radians to degrees
degrees = (180/pi) x radians
What is the equation for converting degrees to radians
radians = (pi/180) x degrees
Define the difference between scalars and vectors
Scalar quantities have a magnitude whereas vectors have a magnitude AND a direction. Scalars can simply be added together whereas vectors usually have to found graphically or via trigonometry
Give some examples of scalar quantities
Mass, distance, speed, temperature
Give some examples of vector quantities
Displacement, angular displacement, acceleration, force, velocity
What does ‘resolving the vector into its components’ mean
Replace each vector with a pair of vectors at right angles to each other which can then be added together
What is the Cartesian system
A reference frame also called rectangular coordinates, It includes x, y and z coordinates. All axes are at right angles to each other (they are orthogonal) and are independent to each other (a change in position on one axis will not affect the others)
What properties must a plane have
Must have zero thickness and be a 2D structure. A straight line is formed where 2 planes cross each other
What is the difference between Cartesian (rectangular) coordinates and polar coordinates
Polar coordinates include angles (therefore they are more useful where angles and rotations are involved)
Define kinematics
The study of motion in terms of how the objects move, but NOT the cause of the movement
What is the maximum degree of freedom
6 degrees of freedom: 3 independent translations and 3 independent rotations
What are the 4 parameters used to describe linear motion
Time, displacement, linear velocity and linear acceleration
What is the difference between speed and velocity
Speed is a scalar quantity which is the distance travelled divided by time. Velocity is a vector quantity which states the speed AND direction of travel
What are the SI units of velocity
metres per second m s-1
What is the difference between average velocity and instantaneous velocity
Average velocity = change in displacement/time taken whereas instantaneous velocity is the velocity at a given time (measured by drawing a tangent to the displacement-time graph)
What is equal to the gradient of the displacement-time graph
Velocity
What is the definition of acceleration
The rate of change of velocity. It is calculated by change in velocity/time taken
What is equal to the gradient of the velocity-time graph
Acceleration
What is the SI unit of acceleration
metres per second squared (m s-2)
What are the 4 parameters used to describe rotatory motion
Time, angular displacement, angular velocity and angular acceleration
What is angular velocity
The angular displacement/time taken
