Answer:
5 hours
Explanation:
formula is 6 km per hour
if you have to travel 30 km, divide 30 by 6
30/6 = 5 hours
Answer:
301.48 J/s
Explanation:
We are given;
Temperature of the sky dropping to −40∘C: T_o = -40°C = -40 + 273 = 233 K
Temperature of your skin and clothes: T = 30°C = 30 + 273 = 303 K
Body surface area of human body is around 2 m². But here only half of the body is facing the sky, Thus Area is: A = 2/2 = 1 m²
To solve this, we will use the equation for thermal heat transfer known as the Stefan bolt Mann equation.
ΔQ/Δt = εσA(T⁴ - (T_o)⁴)
Where;
ΔQ/Δt is the rate at which you body loses energy by radiation
ε is the emissivity of the human body with a value of 0.97
σ is Stefan boltzmann constant with a value of 5.67 X 10^(-8) W/m².K⁴
Thus;
ΔQ/Δt = 0.97 × 5.67 X 10^(-8) × 1(303⁴ - 233⁴)
ΔQ/Δt = 301.48 J/s
Recall the force applied to a spring and its extension/compression:
F = kΔx
Δx is the change in the spring's length (measured from its original length).
x = 0.7 m
x₀ = 0.4 m
Δx = x-x₀ = 0.7 m - 0.4 m = 0.3 m
F = 23 N
Substitute and solve for k:
23 = k×0.3
<h3>k = 7.67 N/m</h3>
Answer:
5.09 Pa
Explanation:
Area of the circle = πr²
The diameter is given, so 100/2 = 50 m is the radius.
π x 50² = 7854 m²
Pressure = force/area
Pressure = 40000/7854
Pressure = 5.09 Pa
Hope this helps!
