Respuesta :
Answer:
3.8
Step-by-step explanation:
h(t) = -4.9 t² + v₀ t + h₀
Given that v₀ = 0 and h₀ = 70:
h(t) = -4.9 t² + 70
When the rock hits the ground, h(t) = 0.
0 = -4.9 t² + 70
4.9 t² = 70
t² = 14.3
t = 3.8
The rock hits the ground after 3.8 seconds.
Answer: t= 3.8secs
Step-by-step explanation:
h(t)=-4.9t^2+V0t+ h0
At initial velocity time is zero coz initial velocity is zero
H(t)= -4.9t^2+70
At final velocity h(t) is zero
70=4.9t^2
t^2=70/4.9
t^2=14.58
t=3.8secs