Linear Motion

Linear Motion:

By Naomi Keddy

Scalar: is any quantity that has magnitude only (Just a number) eg Speed, time, distance

Vector: is any quantity that has magnitude and direction. eg. Velocity

Speed:

Speed is the distance travelled per unit of time. 

The unit used for speed is  m/s.

Speed is distance divided by time

Distance:

Distance is a scalar quantity. 

The unit used for distance is metre (m)

The symbol for distance is d or s

Distance is time multiply by speed.

Acceleration:

Acceleration is the rate of change of velocity in a given time.

The unit used for acceleration is m/s²

Acceleration is the change in velocity divided by the time taken.

Derive the three equations of motions:

• u= Initial (first) Velocity
• v= Final Velocity
• a= Acceleration
• t= Time
• s= Displacement

Velocity is the speed in a given direction.

Displacement is distance with a direction.

1.    v = u + at

2.    s= ut+ ½at²
3.    v²  = u² +2as

Acceleration due to gravity:

·       The value of gravity is 9.8 m/s

·       G always acts downwards, if g is acting in the direction of the velocity then g is positive.

·       If it acts in the opposite of the body then g is taken as negative. Eg -9.8 m/s