Question

a ball is vertically thrown with a velocity of 98 m/s calculate the maimum height it raches

Answer 1

It helps if you think of g as 9.8 m/s per second and realise at that rate 98 m/s will be gone in 10 seconds. The average upward velocity is 49 m/s so it rises 490 metres.

You could also use the suvat equation with no t which comes from considering energy: v2 = u2 + 2as

With u=98, v=0, a=-9.8 and s as your target.