Problem: A man stands on the roof of a building of height 16.8m and throws a rock with a velocity of magnitude 30.6m/s at an angle of 29.3? above the horizontal. You can ignore air resistance.
Part A: Calculate the magnitude of the velocity of the rock just before it strikes the ground.
Part B: Calculate the horizontal distance from the base of the building to the point where the rock strikes the ground.
I need help to determine the magnitude of the velocity of the rock just before it strikes the ground.