Basics


Mechanics

Mechanics is an old world for the branch of science that deals with the motion of material objects.
We have to understand the distinction between three different terms:
speed, velocity, and acceleration.

Speed
is the distance an object travels devided by the time it takes to travel that distance.

Speed(in m/s) = distance (in m) / time (in s)

s = d / t

Velocity
has the same numerical value as speed but velocity always includes information on the direction of travel. The speed of a car may be 50 km per hour, while the velocity is 50 km per hour due west. This means velocity has a magnitude and a direction.

Acceleration
measures the rate of change of velocity, and the velocity, acceleration has a direction. You are accelerating if you are speeding up, slowing down, or change direction.

Acceleration is the amount of change in velocity devided by the time it takes the change to occur.

acceleration( in m/s2)= [final velocity - initial velocity (in m/s)] / time ( in s)

a = (vt - vi) / t

For objects falling, we observe:

The velocity of a falling object is proportional to the length of time that it has been falling.

velocity (in m/s) = the constant g ( in m/s2) x time ( in s)

v = g*t

The constant is the numerical value for the acceleration we and all other objects experience at the Earth's surface.

g = 9.8 m/s2


Tutorial:

Unit Conversion for Combined Units

Ch. Elster
Aug 26 14:27:03 EDT 2020