Respuesta :

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It will hit the ground when h(t)=0.  Since the hammer is simply dropped its initial velocity, v0, is equal to zero and we are told that the initial height, h0, is 25m so our equation is:

h(t)=-4.9t^2+25, we want h(t)=0 so:

4.9t^2-25=0 add 25 to both sides

4.9t^2=25  divide both sides by 4.9

t^2=250/49, since t>0

t=+√(250/49) seconds

t≈2.3 seconds (to the nearest tenth of a second)

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