UNITS - SI UNITS: 800cm --> 0.8m 0.65kg
a) Ep= mg(change) height
Ep=0.65kg * 9.81m/s2 * 0.80m
Ep=5.10 Joules (J)
b) Gravational Potential = Kinetic energy
Ek = 1/2 mv2
v=Sqrt(Ep/0.5m)
v=sqrt(5.10/0.5*0.65)
v=3.96m/s
c) v=u+ at
t=(v-u)/a
v=3.96m/s u=0m.s a=9.81m/s2
t=3.96/9.81
t=0.40s