6. A boy kicks a football vertically upwards from a height of 0.6 m above the ground with a speed of \(10.5 \mathrm {~ms} ^ { - 1 }\). The ball is modelled as a particle and air resistance is ignored.
- Find the greatest height above the ground reached by the ball.
- Calculate the length of time for which the ball is more than 2 m above the ground.