Hi all, First of all I'd like to say thank you to you all for providing a great forum which has been a great help to me working through my ics home learning course. As i have learnt on here and other places on the internet the information I have in my course materials is not always correct and can be very confusing causing hours of unnecessary extra work. The question I am very stuck on is: Calculate the tension in a 3m string attached to a 3kg bob that is moving in horizontal circles of 0.6m radius. All the information I have on working this out shows that tan should be used to work out the angle, I have questioned this with my tutor and he doesn’t seem to have an answer for me. (What chance have I got?) I have always been very interested in physics and have enjoyed learning throughout the course. I just can’t seem to find a simple clear formula for working this question out? Any help greatly appreciated Many thanks,Dave.