# Basic physics calculators on the net **URL:** \ **Category:** Factual Questions\ **Created:** [June 29, 2007, 8:43pm UTC](https://boards.straightdope.com/t/basic-physics-calculators-on-the-net/409968 "2007-06-29T20:43:41Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![Rhythmdvl](https://avatars.discourse-cdn.com/v4/letter/r/85f322/32.png) [@Rhythmdvl](https://boards.straightdope.com/u/Rhythmdvl)\ **Post date:** [June 29, 2007, 8:43pm UTC](https://boards.straightdope.com/t/basic-physics-calculators-on-the-net/409968/1 "2007-06-29T20:43:41Z")
I’m editing some basic high school science materials. For a while I’ve only had Life Sciences and Chemistry to deal with, the Physics coursework had been going to someone else. But that ended a couple days ago, when on short notice I was asked to take on the Physics materials :eek: I’m (somewhat) fine with the general concepts and whatnot, but checking the math is going excruciatingly slow (the general subject in this round is kinematics). Is there a good, Web-based set of calculators out there that will allow me to plug in various bits of problems and check the author’s math? I’m a wee bit desperate here. For context, the section I’m working on is: > [@](#): > > The height from which the rock falls is 320m; according to my table, this height of free fall corresponds to the time of fall equal to 8 seconds. The motion in a horizontal direction is uniform, with the distance of 48m covered during 8 seconds; thus the initial velocity has a magnitude of 6m/sec and is horizontal in direction, away from the bridge. > > The horizontal component of the final velocity is still 6m/sec in magnitude (it stays constant throughout the projectile motion; the vertical component of the final velocity is found in my table. It corresponds to 8 sec of free fall, and is, therefore equal to 80 m/sec[sup]2[/sup] The bit that’s been sticking in my craw for a bit is figuring out the initial velocity. Is 6m/sec correct? Beats me, everywhere I’ve found wants me to put in initial velocity and solve for the rest, not the other way around. Thanks, Rhythm ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [June 29, 2007, 8:56pm UTC](https://boards.straightdope.com/t/basic-physics-calculators-on-the-net/409968/2 "2007-06-29T20:56:34Z")
The [HyperPhysics](http://hyperphysics.phy-astr.gsu.edu/hbase/hph.html) site includes many calculators. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [June 29, 2007, 8:58pm UTC](https://boards.straightdope.com/t/basic-physics-calculators-on-the-net/409968/3 "2007-06-29T20:58:30Z")
I think in this problem they are telling you how far away the rock landed from it’s initial position in the horizontal direction. Thus, you solve backwards to get the initial velocity, which is correct in this case. 48m/8sec = 6m/sec. ---
**Author:** ![Rhythmdvl](https://avatars.discourse-cdn.com/v4/letter/r/85f322/32.png) [@Rhythmdvl](https://boards.straightdope.com/u/Rhythmdvl)\ **Post date:** [June 29, 2007, 9:20pm UTC](https://boards.straightdope.com/t/basic-physics-calculators-on-the-net/409968/4 "2007-06-29T21:20:42Z")
Thanks **Squink** , HyperPhysics is indeed a great place. The drive-me-up-a-wall-to-post-in-desperation bit was that, while it’s been a lifesaver, the [launch velocity](http://hyperphysics.phy-astr.gsu.edu/hbase/traj.html#tra14) applet doesn’t seem to work ☹ (Or it does and I’m more of a moron than I thought.) ---
**Author:** ![Rhythmdvl](https://avatars.discourse-cdn.com/v4/letter/r/85f322/32.png) [@Rhythmdvl](https://boards.straightdope.com/u/Rhythmdvl)\ **Post date:** [June 29, 2007, 9:38pm UTC](https://boards.straightdope.com/t/basic-physics-calculators-on-the-net/409968/5 "2007-06-29T21:38:19Z")
With apologies to HyperPhysics: The notion just popped into my head to try it with IE, rather than FF, and whoa… it worked perfectly. Oh, and thanks Mr. Mace!