The following equations show how kinetic energy (KE), potential energy (PE), and total mechanical energy (ME) are solved.
KE = 0.5mv²
PE = mgh
ME = PE + KE
where m is mass, v is speed/velocity, g is gravitational constant, and h is height.
Substituting for number 1,
KE = 0.5(2000 kg)(30 m/s)² 900,000 J
PE = (2000 kg)(9.8 m/s²)(0 m) = 0
ME = 900,000 J
I believe you will be able to answer the rest of the items following the same principles as presented above.