1. A particle's acceleration is given by a(t) = cos t i + sin t j + t k. Its initial velocity is v(0) = 0 and its initial position is r(0) = i + j. Find r(t).
2. A projectile is ????red with an initial speed of 200 m/s and angle of elevation 60o. Find the range and the maximum height reached.
3. A projectile is ????red at a position 100 m above the ground, with speed 200 m/s and angle 60o as before. Find its range, maximum height reached as well as speed at impact.
4. Show that a projectile ????red from the ground reaches 3/4 of its maximum height in half the time required to reach its maximum height.

These particular problems are confusing to me if I could get some explanation that would be great!