The height (in meters) of a projectile shot vertically upward from a point 2 m above ground level with an initial velocity of 24.5 m/s is
h = 2 + 24.5t − 4.9t2
after t seconds. (Round your answers to two decimal places.)

Question

The height (in meters) of a projectile shot vertically upward from a point 2 m above ground level with an initial velocity of 24.5 m/s is 
h = 2 + 24.5t − 4.9t2
 after t seconds. (Round your answers to two decimal places.)

anonymous · Answer

With what velocity does it hit the ground?

aum · Answer

When it hits the ground, h = 0.
Set h = 0 and solve the quadratic for t to find the time when it hits the ground.  Discard negative t as extraneous solution.

velocity = dh/dt.  Find the derivative and then substitute the t value found earlier.  That will be the velocity when the projectile hits the ground.  Negative velocity just means the object is traveling down along the negative y-axis.