Answer:
Change in mechanical energy, 
Explanation:
It is given that,
Mass of the projectile, m = 12 kg
Speed of the projectile, v = 20 m/s
Maximum height, h = 18 m
Initially, the projectile have only kinetic energy. it is given by :


K = 2400 J
Finally, it have only potential energy. it is given by :
P = mgh

P =2116.8 J
The change in mechanical energy is given by :



So, the change in mechanical energy is 283.2 J. Hence, this is the required solution.
Answer:
The answer is true
Explanation:
could you brainliest again they said I plagarized when I didn't
Explanation:
The protons determines the atomic number which helps in identifying an atom of an element
Answer:1 because
Explanation: it’s pointing to the earth and gravity
Pulls things down to earth