1) a 2000 kg car is traveling at 30 m/s on a level road .

a) what is the car's kinetic energy ?
b) what is the car's potential energy ?
c) what is the car's mechanical energy ?

2) mark has a mass of 55 kg and climbs up a short, steep trail of length 300 m to reach the top of a 100 m tall cliff. matthew , his twin brother, walks up a gentle, winding trail of length 500 m to reach the top of the same cliff. what is the potential energy of each boy at the top?

3- death valley, california , has an elevation of 86 meters below sea level. what is the potential energy of a 60 kg teacher in death valley?

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.