Answer:
A physical change
Explanation:
You are wiping chalk particles from the board to the eraser which is just changing the location of the chalk particles, a physical change.
you're not changing the chalk into a new substance or causing a chemical reaction, which would be a chemical change.
The intensity of light is related to our perception of brightness.
Like poles repel and unlike poles attract. Magnetic poles always occur in pairs of north and south—it is not possible to isolate north and south poles.
momentum= mass × velocity
p= 50×18
momentum= 900 kg m/s
I can see what i can do if you need assistance
