Answer
10 Seconds
Work Step by Step
h(t)=-16t^2+64t+960
factor -16(t^2-4t-60)
Using ac method, find two numbers whose products are -60 and their sums are -4. The numbers are 6 and -10.
t^2+6t-10t-60
t(t+6)-10(t+6)
(t-10)(t+6)
t+6=0 t=-6 does not make sense
t-10=0 t=10
After 10 seconds the object strikes the ground.
