Two first graders are standing on the bridge, throwing rocks into creek. Bridge is 4 feet above creek. Their older sister is watching and taking notes for physics class: she is to find formula for height of rock above creek at the given time.
i) At time zero, first child throws the rock up into air. Children are at 4 feet above creek already. Find coordinates for rock at instant child throws it in terms of (time, height)?
ii) Rock reaches 8 feet above creek half second after child throws it, and then begins to fall. This is vertex of parabola describing rocks height. Find coordinates of vertex in terms of (time, height)?
ii) Use vertex and coordinate in part (a) to write the formula for height of rock above creek.
iii) If second child throws the rock in exact same way but two seconds later, find formula for its height given elapsed time as first rock was thrown?