Jessica Ennis

Sunday 5 August 2012

For the past week I have been watching the Olympics and being a Brit I've been particularly looking forward to Jessica Ennis performing. Jessica is a heptathlete which means she has to participate in 7 track and field events over two days. Day one includes the shot put. I was impressed with how far she could put the shot and looked up the world record to see how far she was from the women's best. She was putting the shot to about 14m but the world record for women is 22.63m. I was surprised to find out that the men's record  was only a bit longer 23.12m but put this down to a pre drugs testing record, I remember some big women from the 70's. It wasn't until the next morning that I realised why the records are so close, they have different sized shots. Women 4kg, men 7.26kg. So the men's is about twice as big. Now the maximum range for a projectile = v2/g, so proportional to v2. If the men used the same shot as the women and gave it the same amount of KE they give their bigger shot, then it would have a v2 twice as big, resulting in a world record over 40m. Jessica won gold by the way.


Tags: sport