Problema Solution

An object is thrown upward from the top of a 160- foot building with an initial velocity of 48 feet per second. The height h of the object after t seconds is given by the quadratic equation h=-16t^2+48t+160. When will the object hit the ground?

Answer provided by our tutors

The object hits the ground when h(t) = 0 for some t, t>0.

By solving h(t) = 0 that is:

-16t^2+48t+160 = 0

........

click here to see the equation solved for t

........

t = 5 s (We need to ignore the negative solution -2 because the time can only be non-negative)

The object will hit the ground after 5 seconds.