Question 975274
h=-4.9t^2+51t+1.3 
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Max ht is the vertex at t = -b/2a
t = -51/-9.8 = 255/49
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hmax = -4.9(255/49)^2 + 51*255/49 + 1.3
=~ 134 meters
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PS  That's not a rocket.  Rockets have thrust.
It's a projectile.