FORCES & MOTION

Average Speed = Distance moved ÷ Time Taken

A negative acceleration is called Deceleration or Retardation

Average Acceleration = Change in Velocity ÷ Time Taken

A uniform acceleration mean a constant (steady) speed

Motion Graphs

Speed Time Graphs: The gradient of the line is numerically equal to the acceleration & The area under the line is numerically equal to the distance travelled

Distance Time Graphs: The gradient of the line is numerically equal to the speed

Acceleration of Free Fall: the acceleration of a body falling freely in a vacuum near the surface of the earth in the earth's gravitational field: the standard value is 9.806 65 metres per second

A Force is a push or a pull, exerted by one object on another. Force has directions and magnitude

The SI unit of force is the newton

NEWTON'S LAWS

Newton's Second Law: The relationship between Force, mass and Acceleration is known as newton's second law of motion

Newton's Third law of motion: To every action there is an equal but opposite reaction

Newton's First Law: If no external force is acting on it, an object will if stationary, remain stationery & if moving, keep moving at a steady speed in a straight line.

Terminal Velocity : the constant speed that a freely falling object eventually reaches when the resistance of the medium through which it is falling prevents further acceleration.

Inertia: a property of matter by which it continues in its existing state of rest or uniform motion in a straight line, unless that state is changed by an external force.

Resultant Force: If two forces are unbalanced, together they are equivalent to a single force.

Resultant Force = Mass x Acceleration

FRICTION

Static Friction

Dynamic Friction

The downward pull from the earth is the gravitational force

A gravitational field is a region in which a mass experiences a force due to gravitational attraction

Weight = Mass x gravitational field strength

Momentum

Linking force and momentum

Change in Momentum = Resultant force x Time

Momentum = Mass x Velocity

Resultant force = Change in Momentum ÷ Time

Law of Conservation of momentum

When two or more objects act on each other, their total momentum remains constant, provided no external forces are acting upon it