Answer:
the third statement is true
Explanation:
given data
Lenovos cost more than Dells
Lenovos cost less than Apples
solution
we have given 1st statement that is express as
cost (Lenovo) > cost (Dell) ..................1
and
2nd statement that is express as
cost (Lenovo) < cost (Apple)
so we can say it as
cost (Apple) > cost (Lenovo) ......................2
and
now above Both equation 1 and 2 can be written as
cost (Apple) > cost (Lenovo) > cost (Dell) .........................3
so we can say cost of Apples is more than the cost of Lenovos and the cost of Dells
so as that given 3rd statement is true
Answer:
0.0406 m/s
Explanation:
Given:
Diameter of the tube, D = 25 mm = 0.025 m
cross-sectional area of the tube = (π/4)D² = (π/4)(0.025)² = 4.9 × 10⁻⁴ m²
Mass flow rate = 0.01 kg/s
Now,
the mass flow rate is given as:
mass flow rate = ρAV
where,
ρ is the density of the water = 1000 kg/m³
A is the area of cross-section of the pipe
V is the average velocity through the pipe
thus,
0.01 = 1000 × 4.9 × 10⁻⁴ × V
or
V = 0.0203 m/s
also,
Reynold's number, Re = 
where,
ν is the kinematic viscosity of the water = 0.833 × 10⁻⁶ m²/s
thus,
Re = 
or
Re = 611.39 < 2000
thus,
the flow is laminar
hence,
the maximum velocity = 2 × average velocity = 2 × 0.0203 m/s
or
maximum velocity = 0.0406 m/s
Answer:
Recall the formula for the maximum stress, σₐ = 2σ₀ *√ (α/ρₓ)
where
σ₀ = tensile stress = 140 MPa = 1.40x 10⁸Pa
α = crack length = 3.8 × 10–2 mm = 3.8 x 10⁻⁵m
ρₓ = radius of curvature = 1.9 × 10⁻⁴mm = 1.9 × 10⁻⁷m
Substituting these values into the formula, we can calculate the max stress as
====== 2 x 1.40x 10⁸ x √(3.8 x 10⁻⁵/1.9 × 10⁻⁷)
σₐ = 24.4MPa
