The S.I. unit for the measure of the pressure is the Pascal (Pa). 1 Pascal corresponds to
We can convert the number given by the problem into Pascal:
And since
, we have
Answer:
Three lunar eclipses every year.
Explanation:
A lunar eclipse only occurs during a full Moon, when the Sun, Earth and Moon are all aligned. But despite the Moon only taking 29.5 days to orbit Earth and complete a cycle from full Moon to full Moon, there are only on average about three lunar eclipses every year.
You measure the open distance between the floor and the bottom surface of the gas pedal. Then you press the gas pedal down 1/2 of that distance.
Answer:
speed is the rate of change in distance thus it is scalar physical quantity
while velocity is the rate of change in displacement thus it is a vector physical quantity
Explanation:
vector physical quantity: is a quantity that requires both magnitude and direction to identify
scalar quantity: requires only magnitude to identify.
Answer:
31.6 m/s
Explanation:
Mass is conserved, so the mass flow at the outlet of the pump equals the mass flow at the nozzle.
m₁ = m₂
ρQ₁ = ρQ₂
Q₁ = Q₂
v₁A₁ = v₂A₂
v₁ πd₁²/4 = v₂ πd₂²/4
v₁ d₁² = v₂ d₂²
Now use Bernoulli equation:
P₁ + ½ ρ v₁² + ρgh₁ = P₂ + ½ ρ v₂² + ρgh₂
Since h₁ = 0 and P₂ = 0:
P₁ + ½ ρ v₁² = ½ ρ v₂² + ρgh₂
Writing v₁ in terms of v₂:
P₁ + ½ ρ (v₂ d₂²/d₁²)² = ½ ρ v₂² + ρgh₂
P₁ + ½ ρ (d₂/d₁)⁴ v₂² = ½ ρ v₂² + ρgh₂
P₁ − ρgh₂ = ½ ρ (1 − (d₂/d₁)⁴) v₂²
Plugging in values:
579,160 Pa − (1000 kg/m³)(9.8 m/s²)(15 m) = ½ (1000 kg/m³) (1 − (1.99 in / 3.28 in)⁴) v₂²
v₂ = 31.6 m/s
