Re: how far can a bullet travel shot into water?

Re: how far can a bullet travel shot into water?: "Re: how far can a bullet travel shot into water?
Date: Thu Jul 12 13:06:51 2001
Posted By: Jaime Valencia-Rodríguez, Guest Researcher, Chemical Science and Technology Lab, NIST.
Area of science: Physics
ID: 991288529.Ph

Message:


Dear David:

Thank you for your question.
The problem you are addressing is an old one and it looks deceivingly
simple. We need to start mentioning Newton's Second Law. In the following
link there is a nice explanation about this subject:
ballistic trajectories

This page reads in part: 'In this lesson we will experiment with
computing and visualizing ballistic trajectories. A ballistic trajectory
is the path followed by an object which, after it is given some initial
velocity, travels only under the influence of gravity. For the purposes of
this lesson we will ignore the effects of air resistance.'

Well, ignoring air resistance, or, more generally, the medium resistance,
is a huge simplification. Nevertheless, we will go along for the moment.

The Ballistic Trajectory Problem
One of the first problems studied in an introductory physics class is the
ballistic trajectory problem. Let's assume that we are standing in a flat
field and that we throw a ball so that it starts out moving at some
velocity V > 0 and at some angle theta radians with the ground. At any
given time t, the ball's horizontal distance is given by

Vt cos (theta)

and its vertical height is given by

Vt sin(theta) - (1/2)gt^2

where g is the earth's gravitational constant, or 9.8 meters/sec/sec. This
assumes that the ball's initial ho"