Am brand new to this forum. I have recorded my bowling action (the english game of cricket, where you throw/bowl the ball the the batsmen). It was recorded side on to my run up. I wanted to measure my speed, so I thought, using 2 consecutive frames from movie maker, giving a time of 0.04 sec. Then using Pixlr(free photoshop), overlap the two frames, and measure the pixel distance the ball has traveled. Then I use the diameter of the ball (known) to measure how much distance each pixel is in real life. Then I calculate speed.
This should be accurate, with the only uncertainty coming from the pixel measurements. The results so far have me questioning if there are other factors I have missed, I got most of readings at 40mph, this is very slow, spinners bowl at this speed, I have been told I am faster, then I have one reading at 75mph. The fast one showed really good technique, so is why is that fast, but the slower ones shouldn't be that slow.
Thanks so much for the help.