You are to drive to an interview in another town, at a distance of 290 km on an expressway. The interview is at 11:15 A. M. You plan to drive at around 100 km/h, so you leave at 8:00 A. M. to allow some extra time. You drive at that speed for the first 100 km, but then construction work forces you to slow to 35 km/h for 40 km. What would be the least speed needed for the rest of the trip to arrive in time for the interview

The base of a 50-meter tower is at the origin; the base of a 50-meter tree is at (0, 50, 0). the ground is flat and the z-axis points upward. the following parametric equations describe the motion of six projectiles each launched at time t = 0 in seconds. (i) r (t) = (50 + t2)k (ii) r (t) = 2t2 j + 2t2k (iii) r (t) = 50 i + 50 j + (50 − t2)k (iv) r (t) = 2t j + (50 − t2)k (v) r (t) = (50 − 2t) i + 2t j + (50 − t)k (vi) r (t) = t i + t j + tk (a) which projectile is launched from the top of the tower and goes downward? at time t = , the projectile hits the ground at point (x, y, z) = . (b) which projectile hits the top of the tree?