posted by laura .
Re identifying forces, thankyou to Rom for your help, ive now been able to do most of them.
One's i am still stuck on are a bungee jumper, speeding train, cyclist speeding off a ramp and a shuttlecock falling to the ground.
bungee jumper: cord tension and gravity, air friction
speeding train: frictional (driving) force between wheels and track, air friction, rolling friction, gravity (if not level)
cyclist speeding off a ramp: gravity (mostly) and air friction
shuttlecock falling to the ground: gravity and air friction (about equal)