posted by leafprincess .
a bicyclist and his bike have a combined mass of 105 kg. He is traveling at 15.0 m/s along the path when he sees a fallen tree 4 m in front of him. In order to stop before hits the tree, find the boy's minimum acceleration and the minimum force that must be applied.
Use (Vf)^2 = (Vi)^2 + 2as
where Vf is final velocity, Vi is the initial velocicy, a is acceleration, and s is distance.