Answer:
18,375 kJ
Explanation:
Parameters given:
Density of water: 1000 kg/m³
Acceleration due to gravity = 9.8 m/s²
Dimensions of pool = 30m × 10m × 2.5m
Depth of pool = 2.5 m
First we need to find the mass of the water in the pool:
Density = mass/volume
Mass = density * volume
Since the pool is full of water, the volume of the water is equal to the volume of the pool:
Volume = 30 * 10 * 2.5 = 750 m³
Mass = 1000 * 750
Mass = 750,000 kg
We can now find the force required to pump the water out of the pool:
F = m * g
Where m = mass of water
g = acceleration due to gravity
F = 750,000 * 9.8 = 7,350,000 N
The work needed to be done is the product of the force required by the distance the water would need to move to be pumped out (depth of pool):
Work = F * d
Work = 7,350,000 * 2.5
Work = 18,375,000 J = 18,375 kJ
Answer:
a. Velocity
Explanation:
The slope of the tangent line on a position-time graph is the instantaneous velocity.
Answer:
a) K = 0.63 J, b) h = 0.153 m
Explanation:
a) In this exercise we have a physical pendulum since the rod is a material object, the angular velocity is
w² =
where d is the distance from the pivot point to the center of mass and I is the moment of inertia.
The rod is a homogeneous body so its center of mass is at the geometric center of the rod.
d = L / 2
the moment of inertia of the rod is the moment of a rod supported at one end
I = ⅓ m L²
we substitute
w =
w =
w =
w = 4.427 rad / s
an oscillatory system is described by the expression
θ = θ₀ cos (wt + Φ)
the angular velocity is
w = dθ /dt
w = - θ₀ w sin (wt + Ф)
In this exercise, the kinetic energy is requested in the lowest position, in this position the energy is maximum. For this expression to be maximum, the sine function must be equal to ±1
In the exercise it is indicated that at the lowest point the angular velocity is
w = 4.0 rad / s
the kinetic energy is
K = ½ I w²
K = ½ (⅓ m L²) w²
K = 1/6 m L² w²
K = 1/6 0.42 0.75² 4.0²
K = 0.63 J
b) for this part let's use conservation of energy
starting point. Lowest point
Em₀ = K = ½ I w²
final point. Highest point
Em_f = U = m g h
energy is conserved
Em₀ = Em_f
½ I w² = m g h
½ (⅓ m L²) w² = m g h
h = 1/6 L² w² / g
h = 1/6 0.75² 4.0² / 9.8
h = 0.153 m
Answer:
they were slaves, so they did practically everything anyone didn't do.
Explanation:
btw, which war? or battle?