Answer:
Option B.
Explanation:
Assuming the stick is in vertical position, its shadow depends on two factors: its length and the angle between the sun rays and the stick. When the angle is bigger, the lenght of the shadow increases, and vice versa. So, when the sun rays are parallel to the stick, the shadow may be small. Since they are nearly perpendicular to the Earth's surface at 12 o'clock, the shadow of the stick at that time should be minimal. It means that the measured shadow of 75 cm at 12:30 p.m. is almost impossible (Option B).
Explanation:
The kinetic energy of an object is given in terms of its mass and object as :

An object with more mass has more kinetic energy. An object with less mass, if both objects are moving at the same speed, in opposite directions, will have less kinetic energy. The square of v will give positive number.
That is -300 J, because the work = the force times the distance. When the distance is a positive value when it is going down, the distance is a negative value when it is going up. The only thing that change is the minus, the absolute value of the work remains the same