4. At time \(t = 0\), two balls \(A\) and \(B\) are projected vertically upwards. The ball \(A\) is projected vertically upwards with speed \(2 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) from a point 50 m above the horizontal ground. The ball \(B\) is projected vertically upwards from the ground with speed \(20 \mathrm {~m} \mathrm {~s} ^ { - 1 }\). At time \(t = T\) seconds, the two balls are at the same vertical height, \(h\) metres, above the ground. The balls are modelled as particles moving freely under gravity. Find

1. the value of \(T\),
2. the value of \(h\).