Answer:
121.0 W
Explanation:
We use the equation for rate of heat transfer during radiation.
Q/t = σεA(T₂⁴ - T₁⁴)
Since temperature of surroundings = T₁ = -20.0°C = 273 +(-20) = 253 K, and temperature of skier's clothes = T₂ = 5.50°C = 273 + 5.50 = 278.5 K.
Surface area of skier , A = 1.60 m², emissivity of skier's clothes, ε = 0.70 and σ = 5.67 × 10⁻⁸ W/m²K⁴
.
Therefore, the rate of heat transfer by radiation Q/t is
Q/t = σεA(T₂⁴ - T₁⁴) = (5.67 × 10⁻⁸ W/m²K⁴
) × 0.70 × 1.60 m² × (278.5⁴ - 253⁴) = 6.3054 × (1918750544.0625) × 10⁻⁸ W = 1.2098 × 10² W = 120.98 W ≅ 121.0 W
Answer:
12.74 ms^-1 download
Explanation:
v=28.2, a=9.81
start from rest u=0
v=u+at=0+(9.81)t=28.2
t=2.875...
it reach 1.4 second before hitting the ground:
t=1.4, u=0, a=9.81
v=u+at=0+(9.81)(1.4)=12.74
Answer:
I believe it's 8.09 seconds, but I'm rusty on my physics.
Explanation:
The equation for solving the time it takes for an object to fall is 
So multiply the distance times 2, and you get 642 meters. Then you divide by gravities acceleration constant, 9.8, and you get 65.51. Finally, 
, and you get 8.09 seconds.
I pulled the equation off of wikipedia and I'm unsure if it's the correct one, so hopefully this is correct. :/
Answer:
230.4 N
Explanation:
From the question given above, the following data were obtained:
Charge (q) of each protons = 1.6×10¯¹⁹ C
Distance apart (r) = 1×10¯¹⁵ m
Force (F) =?
NOTE: Electric constant (K) = 9×10⁹ Nm²/C²
The force exerted can be obtained as follow:
F = Kq₁q₂ / r²
F = 9×10⁹ × (1.6×10¯¹⁹)² / (1×10¯¹⁵)²
F = 9×10⁹ × 2.56×10¯³⁸ / 1×10¯³⁰
F = 2.304×10¯²⁸ / 1×10¯³⁰
F = 230.4 N
Therefore, the force exerted is 230.4 N
To solve this problem, we have to use the formula:
E = h f
where E is total energy, h is Plancks constant
6.626x10^-34 J s, f is frequency
f = E / h
f = 3.686 × 10−24 J / (6.626x10^-34 J s)
<span>f = 5.56 x 10^9 Hz</span>
