The formula of the kinetic energy is KE = 0.5*m*v^2.
Given m = 80 kg and KE = 4000 J,
4000 = 0.5*80*v^2
v^2 = 100
v = 10 m/s
In order for magma to form, wet or dry melting of rocks or minerals must occur. Dry melting occurs when minerals or rocks, with no carbon dioxide or water in them, are heated to a specific temperature.
because speed can change overtime for a car, and isn't always constant.