kid bever

So during the review, he realized that he had made that mistake and he was pretty flustered. THere were other people that had come to the same conclusion that I had. Thanks again for your help!

Ok... Thanks. At least I know I'm right. It sucks as a first year, non physics major, to stare at a "simple" problem for two hours only to discover that I was right in the first ten minutes. (Hair ripping out). I'm in class on Tuesday. I'll bring it up then. Best Bruce

Mooey~ I follow your math perfectly. I got 145 feet as well. My professor, however ended up with 316 feet... somehow. I have no clue how. Can you tell me how to illustrate the math the way you did, so I can more clearly demonstrate what he did? Thanks Bruce OK, I looked more closely at the math you used to emulate my instructor, and yes that's exactly what he did. Although he rounded his number 108 rather than 107 which I think is what ends up giving me 316ft and you 309ft. FYI, we normally do use SI, but since this was a baseball question he was using it to throw us "a curve" of sorts. (bad pun intended). can you now illustrate flight time (tf)using the same information? He came up with 1.56 seconds and I got 2.29 Flight time, is straight up algebra... I just multiplied all the variables, seemed pretty straightforward. 2times initial velocity over local gravity (32ft/s/s) times the sine of the launch angle (30 deg). 73.35 ft/s x two = 146.7ft/s divided by 32 ft/s/s = 4.584s times cosine of 30 (.5)= 2.29 Where in the heck did he get 1.56s ?? Am I missing something here?

a ball is struck while traveling 50mph. It's launch angle is 30 deg. Using constant for g= 32ft/s/s calculate the distance the ball traveled. I have the answer. It's 316 ft, according to my professor. What I don't understand is this: When converting 50mph to ft/s you multiply by 1.467. Then in the equation you square that number and divide by g (32). BUT he squared 1.467 FIRST, then multiplied by 50. which gives a different answer than if you convert to ft/s first and THEN square. The formula I'm using reads like this R= Vi2sin(2θ) g R= (Velocity initial)2 times the sine of (2*the angle of launch (or theta)) ---------------------------------------------------------------------------------- 32 ft/s/s SO I converted 50mph to 73.35 ft/s and squared that. BUT MY PROF squared 1.467 to 2.15 THEN multiplied by 50 to get 108. I hope that looks right. I know this isn't difficult math, but I just don't understand why he squared the conversion factor RATHER THAN doing the conversion and squaring the answer. Thanks Bruce