Topic 2.1 Kinematics Flashcards
Define displacement
o Displacement: The distance travelled in a particular direction from a specified origin. A vector.
Define velocity
o Velocity: The rate of change of displacement with time. A vector. Unit: ms-1
Define speed
o Speed and Distance: The scalar versions of velocity and displacement.
Define acceleration
o Acceleration: The rate of change of velocity with time. A vector. Unit ms-2
• 2.1.2: Explain the difference between instantaneous and average values of speed, velocity and acceleration
o Instantaneous: The value of a quantity measured at an instant in time, as opposed to an average quantity measured over a period of time.
• 2.1.4: Identify the acceleration of a body falling in a vacuum near the Earth’s surface with the acceleration g or free fall
o Acceleration Due to Gravity: Ignoring air resistance, a free-falling object accelerates at the surface of the Earth at approx. 9.8ms-2 This is numerically equal to gravitational field strength.
• 2.1.6: Describe the effects of air resistance on falling objects
o Terminal Velocity: Air resistance is proportional to speed, so an accelerating object will achieve terminal velocity
Calculate and interpret the gradients of displacement-time graphs
o DISPLACEMENT-TIME GRAPHS: Gradient is velocity.
Calculate and interpret the gradients and area under the curve of velocity-time graphs
o VELOCITY-TIME GRAPHS: Gradient is acceleration. Area under graph is displacement.
Calculate and interpret the area under the curve of acceleration-time graphs
o ACCELERATION-TIME GRAPHS: Area under graph is change in velocity.
Define relative velocity
o RELATIVE VELOCITY: A velocity measured from the point of view of another moving object (eg the velocity of a car with respect to the bicycle it passes).
