Final answer:
Good marksmanship involves hitting the intended target spot consistently. In physics terms, a bullet sighted at 100 m will drop more when aimed at 150m due to gravity. Higher muzzle velocity reduces bullet drop, while air resistance increases it.
Step-by-step explanation:
Good marksmanship is defined as hitting the spot where you are aiming on your target consistently. To address the specifics of the physics problem presented:
(a) Bullet Drop Calculation
If a gun is sighted for 100.0 m, but the target is 150.0 m away, the bullet will drop more than expected due to gravity. Without considering air resistance and assuming a uniform gravitational pull, the bullet will travel longer in the air, thus falling lower than a target at 100 m.
(b) Muzzle Velocity and Air Resistance
An increase in muzzle velocity would result in a reduced time of flight for a given distance, meaning the bullet would not drop as much before reaching the target. However, assuming a constant gravitational acceleration, this doesn't change the vertical component of the motion, just the total time the bullet is subject to gravity. The effect of air resistance decreases the bullet's velocity over time, so it has more time to fall and will hit lower than expected without air resistance.