mass of car = 1300kg
mass of passenger = 5×40kg = 200kg
Total mass ,m = 1300kg + 200kg = 1500kg
distance travelled ,s= 20m and time = 4sec
by s = ut + 1/2at^2
20 = 0 × 4 + 1/2 (a)4×4
20= 8a
a =2.5m/s^2
by
v=u+at
v= 0 + 2.5 × 4
v= 10 ms/s2
kinergy energy = 1/2 ×15000 × 10×10
= 7500000 j
work done by gravity = -mgh