speed vs velocity

Inertia

A measure of how difficult it is to change an objects motion

The higher an objects mass…

The higher its inertia

Weight

The force that acts on an object when it is in a gravitational field

Weight is the ____ that acts on an object when it is in a gravitational ____

Force, field

Weight =

Mass x GFS

Centre of mass

The point through which an objects weight appears to act

An object will fall over if…

Its centre of mass is outside its base

Why shouldn’t lots of people stand on the top deck of a bus?

• more people on the top deck means the C.O.M will be higher (as more mass is concentrated there)

• Therefore, a smaller tilt of the bus is required to place its C.O.M outside of its wheels- causing it to tilt

Velocity

Describes an objects direction as well has speed. It is a vector.

Is velocity a scalar or vector?

A vector

is speed a scalar or vector and why?

Scalar because you do not need to state its direction

Vector quantity

Have both magnitude and direction

Scalar quantities

Have magnitude only

If two people stand back to back to eachother and walk away from eachother at the same speed…

• they will both have the same ____.

  BUT

• one will have a _____ velocity and the other will have a negative _____.

Speed, positive, velocity