hit, crash, collide

hit
碰撞[(+against)]
The ball hit against the window.
球撞在窗子上。
The ship hit a rock and wrecked.
船触礁撞毁了。

crash
(发出猛烈声音地)碰撞,倒下,坠落
The motorcycle crashed into the fence.
摩托车猛地撞在篱笆上。
(飞机等)坠毁,撞坏
An airliner crashed west of Denver last night.
昨夜一架客机在丹佛西边坠毁。

collide
碰撞;相撞
They collided with another ship.
他们的船与另一条船相撞。

就你第二个问题，我查过字典
collide通常是两辆车撞在一起
crash也比较少用於车撞到人
所以hit应该较适合
E.g.:The man is hit by a car.