Answer:

Explanation:
We know that:

where
is the initial energy,
is the final energy and
is the energy lost due to friction.
so:

Where M is the mass and V is the velocity of the runner, so:


Mechanical waves nees a material medium to propagate
Electromagnetic waves can propagate in vaccum
From my understanding, the two are opposite. Let me give you each word and what it scientifically means to me.
repetition
occurs when an activity is repeated by the same person
replication
occurs when an activity is repeated by a different person
I hope this completely answers your question! If you need further explanation, please let me know!
~Brooke❤️
It is is real because potential energy is stored inside gravitational energy.