field acceleration

by yourdadonapogostick
Tags: acceleration, field
yourdadonapogostick is offline
Jul7-05, 09:36 PM
P: 266
the magnitude of the gravitational field vector, [tex]\vec{G}[/tex], is equal to g at that point. does that mean that magnitudes of [tex]\vec{B}[/tex] and [tex]\vec{E}[/tex] are equal to the acceleration due to magnetism and electric fields, respectively, at a point?
Phys.Org News Partner Physics news on
Better thermal-imaging lens from waste sulfur
Scientists observe quantum superconductor-metal transition and superconducting glass
New technique detects microscopic diabetes-related eye damage
sniffer is offline
Jul8-05, 01:14 AM
P: 112
gravity is different, since the force acting on a mass is proportional to the mass, thus you get a "constant".
yourdadonapogostick is offline
Jul8-05, 01:16 AM
P: 266
with electricity, the force is proportional to the charge.

marlon is offline
Jul8-05, 03:10 AM
marlon's Avatar
P: 4,008

field acceleration

When you write down the equation for the gravitational force you get :

[tex] \frac {Amm'}{r^2}[/tex]

A is the universal gravitational constant, m amd m' the two masses and r is the distance between those two masses. The above formula is ofcourse the component of the interaction along the axis that connects the two masses.

Now write this force as [tex]mG[/tex] then [tex]G = \frac {Am'}{r^2}[/tex]

Suppose you look at an object with mass m on this earth. You describe the gravitational interaction between this object and the earth by setting m' equal to the earth's mass, A is a universal constant, and r is the earth's radius. Now, if this object is 100 above the earth's surface, you should have written for r the value of the earth's radius PLUS 100m. But since the earth's radius is much bigger, just forget about the 100m

If you fill in these values for G, you will get the 9.81 m/s^2 that we all know.
The expression for G which depends on the mass m' and the distance between m and m' also suggest why the gravitational constant is not everywhere the same value on this earth. Well, the earth is not a perfect sphere right

hope that helps

Meir Achuz
Meir Achuz is offline
Jul8-05, 01:46 PM
Sci Advisor
HW Helper
P: 1,930
E and B produce force by the Lorentz force equation:
This equals the rate of change of momentum: dp/dt.
Non-relativistically, dp/dt=ma, but in SR the acceleration is much more complicated.
dp/dt is still relatively simple in SR.

Register to reply

Related Discussions
Fluid Mechanics local acceleration and convective acceleration Advanced Physics Homework 1
help with electric field acceleration problem. Introductory Physics Homework 2
Centripetal acceleration, incorporating a change in acceleration around the circle... Introductory Physics Homework 3
Uniform Circular Motion: Centripital Acceleration vs. Acceleration Introductory Physics Homework 4
given velocity and acceleration, determine magnetic field General Physics 1