Protons copy the number equal
Friction is the force you get when you (for example) Rub something with another, it's a force that may generate heat and even some resistance. Another example is rubbing your hands together, they get hot, therefore friction is working, without friction you wouldn't be able to stop moving.
C) Radiation that comes from Earth...... Hope it helps, Have a nice day :)
I believe this would be an example of Mary's velocity. We have her speed and direction which is all you need to find velocity.
