Answer:
mass.
Explanation:
other physical factors are changeable but the mass of a particular substance is always constant.
Answer:
Velocity = 0.5 m/s South (A)
Explanation:
You need to determine the average rate of velocity.
The equation you will use is velocity = displacement/time
The displacement is 30m South.
The time is 60 seconds.
Plug into the equation Velocity = 30m South/60 s
Velocity = 0.5 m/s South