Question

If a man wants to hit a target, he should aim his rifle in a direction.
A) Lower than the target
B) Of the target
C) Either (a) or (b)
D) Higher than the target

Answer 1

Hint: When a bullet is fired from a rifle, it has a high horizontal velocity due to the force from the gun. However, it will also experience gravitational acceleration which will pull the bullet towards the ground and deviate it from the desired trajectory.

Complete step by step answer:
When a bullet is fired from the gun, the bullet travels in the horizontal line. However, at the same time, gravity pulls the bullet downwards. This can result in the net trajectory of the bullet to have deviated from the desired trajectory.
The amount of deviation in the downwards direction depends on the time taken by the bullet to reach the target. The longer the time is taken by the bullet to reach the target, the more the deviation of the bullet from the initial horizontal trajectory.
Hence to compensate for this downward vertical shift due to gravity, the man must aim his rifle higher than the target. This ensures that by the time the bullet reaches the target, the vertical offset of the direction in which the bullet was fired will be compensated by the gravitational force that would act on the bullet.

Hence the correct choice is option (D).

Note: The direction of the rifle is often measured in terms of angles with respect to the horizontal. Farther the target, the higher you would have to aim the rifle to hit the target. For long-range sniper rifles, the bullet can experience a downwards shift of a few tens of meters which must be compensated for by firing upwards. Over long distances, wind can also play a significant role in deviating the bullet but we have ignored that here.