It's downward vector from the centre of apple in the direction to the centre of the Earth.
Answer: (d)
Explanation:
Given
Mass of object 
Speed of object 
Mass of object at rest 
Suppose after collision, speed is v
conserving momentum

Initial kinetic energy

Final kinetic energy

So, it is clear there is decrease in kinetic energy . Thus, energy decreases and velocity becomes 2 m/s.
Answer:
B : It will avoid the distortion from the atmosphere and give scientists more accurate data
Explanation:
The energy of the wave will decrease.
The energy of a wave is given as
E = h f
where E = energy of waver
h = plank's constant
f = frequency of the wave.
From the formula , we see that the energy of the wave is directly proportional to the frequency of the wave. hence as the frequency of the wave decrease, the energy of the wave will decrease.
This method is known as linear perspective.
When using linear perspective, artists use a set of drawn or imaginary lines which are made to converge at the horizon of the image. These lines change the viewer's perspective by providing a point through which the relative size, shape and position of objects is determined. This technique creates the illusion of depth.