FRAMES OF REFERENCE & RELATIVE MOTION SPH4U – Unit 1 Dynamics

FRAME OF REFERENCE

| Frame of Reference – a coordinate system relative to which motion is described or observed

Examples: - cartesian grid ( x-y axis) - Compass rose

INERTIAL FRAME OF REFERENCE

| A frame of reference that moves at a zero or constant velocity

| A frame in which the law of inertia holds

NON-INERTIAL FRAME OF REFERENCE

| A frame of reference that accelerates with respect to an inertial frame

| The law of inertia does not hold

FICTITIOUS FORCE

| An apparent but non-existent force invented to explain the motion of objects within an accelerating (non-inertial) frame of reference

APPARENT WEIGHT – VERTICAL ACCELERATION

| The magnitude of the normal force acting on an object in an accelerated (non-inertial) frame of reference

SOLVING PROBLEMS RELATING TO APPARENT WEIGHT IN A NON-INERTIAL FRAME OF REFERENCE

RELATIVE MOTION

| Examples: y An airplane flying in the air (motion relative to the earth) y A boat moving in a river (motion relative to the earth)

What does the speedometer say? How fast is it actually moving?

RELATIVE VELOCITY

| The velocity of an object relative to a specific frame of reference y An airplane relative to the earth

USING TRIGONOMETRY WITH RELATIVE MOTION

HOMEWORK

| Read pgs. 108 – 113 | Pg. 112 Practice #1 | Read pgs. 44 – 49 | Pg. 47-48 # 1-3