Forces and Motion
Quantities
Distance and Displacement
Speed
Graphs
Formulas and units
Acceleration
Scalar quantities
Vector quantities
Physical quantities expressed in terms of both magnitude and direction, Expressed in terms of numerical value, unit, and direction. Eg. Displacement, force, weight, acceleration.
Physical quantities only expressed by their magnitude, Expressed in terms of numerical value of quantity and unit measured in. Eg. mass, time, energy.
Distance: It is the length of the actual path taken by an object from it's starting to it's final point
Displacement: Length of the shortest path, usually a straight line between the starting and ending point of motion of an object.
Speed is the distance travelled over a unit time by a body
Instantaneous speed: The distance/time of an object over a very small time interval, basically the speed of an object at a particular moment or instant of time.
AVERAGE SPEED is the total distance travelled by an object divided by the total time it takes to cover that distance. It is = instantaneous speed when the object is in uniform motion throughout.
Distance and displacement : m, km, cm, mm, etc.
Speed and velocity : m/s, km/hr., etc. Speed and velocity are calculated using the formula v = d/t, or speed or velocity = distance / time.
Speed Vs Velocity: Speed is distance by time, it is a scalar quantity, and is only expressed in positive numbers. Velocity can be a negative number if going in opposite direction because it is speed in a particular direction, and it is a vector quantity.
Acceleration: calculated as a = (v - u)/t, or acceleration = final velocity - initial velocity / time taken for the change. Unit is m/s^2, km/h^2, etc.
Rate of change of velocity/speed. When an object speeds up it accelerates, when it slows down it decelerates, these are also called positive and negative acceleration. Acceleration is affected by 2 factors - change in speed of an object, and even change in direction of an object.
Distance/ Time Graphs: They plot the distance covered by an object over time visually. Their line and purpose is to show the SPEED of an object. When an object has no speed, it is a flat horizontal line, when moving constantly, it is a straight diagonal line from the starting point, and with constant acceleration, it is a back curve moving upwards.
Speed/Time graphs: They plot the speed covered by an object over time, their line and purpose is to show the ACCELERATION of an object. When there is no speed, there is a flat line immediately at Zero of the speed scale extending, when there is constant speed it is a flat horizontal line, and when it is constant acceleration it is a straight diagonal line from the starting point.