The kinetic energy of an object is given by
KE = 0.5mv²
where m is the mass and v is the velocity.
To calculate the change in kinetic energy...
Initial KE:
KEi = 0.5mVi²
where Vi is the initial velocity.
Final KE:
KEf = 0.5mVf²
where Vf is the final velocity.
ΔKE = KEf - KEi
ΔKE = 0.5mVi² - 0.5mVf²
ΔKE = 0.5m(Vf²-Vi²)
Given values:
m = 16kg
Vi = 25m/s
Vf = 20m/s
Plug in the given values and solve for ΔKE:
ΔKE = 0.5×16×(20²-25²)
ΔKE = -1800J