7 The equation of the trajectory of a projectile is \(y = 0.6 x - 0.017 x ^ { 2 }\), referred to horizontal and vertically upward axes through the point of projection.
- Find the angle of projection of the projectile, and show that the initial speed is \(20 \mathrm {~m} \mathrm {~s} ^ { - 1 }\).
- Find the speed and direction of motion of the projectile when it is at a height of 5.2 m above the level of the point of projection for the second time.