IP2U4 Exercise Q13

Susan stands at the end of a cliff and throws a ball vertically upwards. The height of the ball above the top of the cliff after \(t\) seconds is \(h\) metres, where \(h=17t-5{{t}^{2}}\).

1. Find the height of the ball when \(t=5\).
2. After how many seconds is it \(6\)m above the top of the cliff?
3. Susan throws a second ball, in exactly the same way, \(4\) seconds after she has thrown the first. Find how far apart the two balls are in vertical direction, one second after the second ball is thrown.