SUMMARY NOTES -MOTION, SPEED, VELOCITY & ACCELERATION

How Does the Object with Zero (0) Acceleration Move?

Object moves at a constant speed or is not moving

How Does the Object with Negative (-) Acceleration Move?

Object slows down

How Does the Object with Positive (+) Acceleration Move?

Object speeds up

According to the formula triangle, the formula for calculating time is

T = D / S.

On a distance-time (D-T) graph, a constant (i.e. line has no curve) indicates that the speed of the object is

constant and therefore the acceleration is zero.

On a distance-time (D-T) graph, a decreasing slope (i.e. line curves downwards) indicates that the speed of the object is

decreasing and therefore the acceleration is negative.

Velocity is a measurement of an object's speed and its

direction.

The distance and direction an object moves from a starting point is known as its

displacement.

In this type of graph, time is plotted on the X-axis while

distance is plotted on the Y-axis.

Graphs that compare distance and time are called

distance-time (D-T) graphs.

Vf stands for

final velocity

On a distance-time (D-T) graph, an increasing slope (i.e. line curves upwards) indicates that the speed of the object is

increasing and therefore the acceleration is positive.

Vi stands for

initial velocity.

Distance

is a measurement of how far an object moves in total.

Distance is measured using the SI unit of

meters (m).

Therefore, speed is measured in the derived SI unit of

meters per second (m/s).

Vf and Vi are velocities measured using the derived SI unit of

meters per second (m/s).

Acceleration is measured in the derived units of

meters per second squared (m/s2).

On a speed-time (S-T) graph, a line moving downwards indicates

negative acceleration.

On a speed-time (S-T) graph, a line moving upwards indicates

positive acceleration.

A car approaching a red traffic light and slowing down displays negative acceleration. When the traffic light turns green and the car moves faster, it's acceleration is

positive.

On a D-T graph, a steep line indicates that an object is moving

quickly.

Time is measured using the SI unit of

seconds (s).

On a D-T graph, a shallow line indicates that an object is moving

slowly.

Instantaneous

speed is a measurement of an object's speed at an exact moment in time.

Average

speed is the total distance traveled divided by the total time the object took.

Constant

speed occurs when an object is traveling at the same speed every second.

Acceleration occurs when an object changes

speed or direction or both.

On a distance-time (D-T) graph, the slope of the line represents the object's

speed.

On a D-T graph, a completely horizontal line indicates that an object is

stopped.

Speed is defined as

the distance an object travels per unit of time.

When the slope of a D-T graph is negative (i.e. moving downwards), the object is moving

towards the reference point.

Velocity is a type of measurement called a

vector, which has both magnitude and direction.

On a speed-time (S-T) graph, a horizontal line indicates

zero acceleration.

The formula for calculating acceleration is

a = (Vf - Vi) / t.

When the slope of a D-T graph is positive (i.e. moving upwards), the object is moving

away from the reference point.

The formula for calculating the speed of an object is

D = S / T

According to the formula triangle, the formula for calculating distance is

D = S x T.