Estimate the force that a cyclist travelling at 6m/s needs to apply to the brakes to bring the bicycle to a stop in a distance of 15m. ignore air resistance & friction.

v1 = 6m/s

v2 = 0

∆v = v1 - v2 = 6m\s

s = t * v = 15m

t = s\v1 = 15(m) \ 6(m\s) = 2.5s

a = ∆v\t = 6(m\s) \ 2.5s = 2.4m\s2

a = F\m = 2.4m\s2

F = a * m = 2.4m\s2 * ?kg

I can't tell you this because I don't know the mass of this cyclist

k2s for potassium sulphide

according to jean piaget, in what stage of cognitive development are children able to understand conservation task?

b. preoperational

just took it