To solve this problem it is necessary to apply the concepts related to Normal Force, frictional force, kinematic equations of motion and Newton's second law.
From the kinematic equations of motion we know that the relationship of acceleration, velocity and distance is given by

Where,
Final velocity
Initial Velocity
a = Acceleration
x = Displacement
Acceleration can be expressed in terms of the drag coefficient by means of
Frictional Force
Force by Newton's second Law
Where,
m = mass
a= acceleration
Kinetic frictional coefficient
g = Gravity
Equating both equation we have that



Therefore,


Re-arrange to find x,

The distance traveled by the car depends on the coefficient of kinetic friction, acceleration due to gravity and initial velocity, therefore the three cars will stop at the same distance.
work done is product of force and displacement of point of application of force
so here we have to check the product of force and displacement both
Now we will put the least to maximum work in the following order
1. -A man exerts strenuous effort in pushing a stationary wall
2. -A flea pushes a speck of dirt 1 cm
3. -A farmer pushes a 2 kg wheelbarrow 20 m
4. -A cannon launches a 3 kg cannonball a distance of 200
5. -A 2000 kg car travels 400 m down a road
6. -Space shuttle Atlantis launches from the ground into near-Earth orbit
Answer:
SUNLIGHT OR SUNRAYS OR ENERGY OR HEAT
Explanation: