AP Free Response Question
2003 B3
Printer Friendly Version
A rail gun is a device that propels a projectile using a magnetic force. A simplified diagram of this device is shown above. The projectile in the picture is a bar of mass
M
and length
D
, which has a constant current
I
flowing through it in the +y-direction, as shown. The space between the thin frictionless rails contains a uniform magnetic field
B
, perpendicular to the plane of the page. The magnetic field and rails extend for a distance
L
. The magnetic field exerts a constant force
F
on the projectile, as shown. Express all algebraic answers to the following parts in terms of the magnitude
F
of the constant magnetic force, other quantities given above, and fundamental constants.
(a) Determine the position
x
of the projectile as a function of time
t
while it is on the rail if the projectile starts from rest at x = 0 when t = 0.
(b) Determine the speed of the projectile as it leaves the right-hand end of the track.
(c) Determine the energy supplied to the projectile by the rail gun.
(d) In what direction must the magnetic field
B
point in order to create the force
F
? Explain your reasoning.
(e) Calculate the speed of the bar when it reaches the end of the rail given the following values.
Topic Formulas
Description
Published Formula
Faraday's Law
magnetic field around a current-carrying wire
magnetic flux
magnetic force on a current-carrying wire
magnetic force on a moving charge
Related Documents
Lab:
Labs -
Forces Between Ceramic Magnets
Labs -
Magnetic Field in a Solenoid
Labs -
Mass of an Electron
Labs -
Telegraph Project
Resource Lesson:
RL -
A Comparison of RC and RL Circuits
RL -
A Guide to Biot-Savart Law
RL -
Ampere's Law
RL -
Eddy Currents plus a Lab Simulation
RL -
Electricity and Magnetism Background
RL -
Famous Experiments: Cathode Rays
RL -
Introduction to Magnetism
RL -
LC Circuit
RL -
Magnetic Field Along the Axis of a Current Loop
RL -
Magnetic Forces on Particles (Part II)
RL -
Magnetism: Current-Carrying Wires
RL -
Maxwell's Equations
RL -
Meters: Current-Carrying Coils
RL -
Torque on a Current-Carrying Loop
Worksheet:
APP -
Maggie
APP -
The Tree House
CP -
Magnetism
NT -
Bar Magnets
NT -
Magnetic Forces
NT -
Meters and Motors
WS -
Magnetic Forces on Current-Carrying Wires
WS -
Magnetic Forces on Moving Charges
WS -
Practice with Ampere's Law
TB -
36A: Magnets, Magnetic Fields, Particles
TB -
36B: Current Carrying Wires
TB -
Exercises on Current Carrying Wires
CB-ETS
Copyright © 1970-2022
All rights reserved.
Used with
permission
Mainland High School
Daytona Beach, FL 32114