Answer:
315 cm
Step-by-step explanation:
The volumetric flow is:
Q = vA
Q = v (πr²)
Q = (70 cm/s) π (2 cm)²
Q = 280π cm³/s
After 30 minutes (1800 seconds), the volume change is:
ΔV = Q Δt
ΔV = (879.6 cm³/s) (1800 s)
ΔV = 504,000π cm³
The increase in water level is therefore:
ΔV = A Δh
ΔV = πR² Δh
504,000π cm³ = π (40 cm)² Δh
Δh = 315 cm
