Heat lost or gained, H = mc(θ₂ - θ₁)
Where m = mass, c = Specific heat capacity, θ₂= final temperature, θ₁ = initial temperature
m = 200g, c = 0.444 J/g°C, θ₁ = 22 °C (Since it was cooled).
H = 6.9 kj = 6.9 *1000J = 6900 J
6900 = 200*0.444* (θ₂ - 22)
6900/(200*0.444) = θ₂ - 22
77.70 = θ₂ - 22
θ₂ - 22 = 77.7
θ₂ = 77.7 + 22 = 99.7
So initial temperature before cooling ≈ 100°C . Option C.
Answer:
29.16 J
Explanation:
From Hook's law,
W = 1/2(ke²)..................... Equation 1
Where W = work done, k = Spring constant, e = extension.
Given: W = 9 J, e = 0.5 m.
Substitute into equation 1
9 = 1/2(k×0.5²)
Solve for k
k = 18/0.5²
k = 72 N/m.
The work done required to stretch the spring by additional 0.4 m is
W = 1/2(72)(0.4+0.5)²
W = 36(0.9²)
W = 29.16 J.
14.8m/s is minimal horizontal velocity must the cliff divers leave the top of the cliff is they are to miss the rock.
Ledge divers in Acapulco leap into the water from a 36-meter-high cliff. A rock protrudes 10.4 meters horizontally from the water, level. 9.8 m/s2 is the acceleration of gravity. If the cliff divers are to miss the rock, they must depart from the top of the cliff with a minimal horizontal velocity.
from above statements, we assume that
there is no initial vertical velocity, then we calculate the time it takes to reach the water, then divide the horizontal distance by that time to get the minimum required horizontal speed.
h=gt^2/2
h= 36 m
t =
put h = 36 m g = 9.8 m/s^2
t=2.7 second
Then the minimum required horizontal velocity is
v = d/t
by putting value
v= 10.4 m/2.7 s
v=14.8m/s
To know more about horizontal velocity visit : brainly.com/question/14059839
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This is what I found online: "<span>For a person with normal hearing, when it comes to pitch the human hearing range starts low at about 20 Hz. That’s about the same as the lowest pedal on a pipe organ. On the other side of the human hearing range, the highest possible frequency heard without discomfort is 20,000Hz. While 20 to 20,000Hz forms the absolute borders of the human hearing range, </span>our hearing is most sensitive in the 2000 - 5000 Hz frequency range<span>." So i'm guessing it's 100,00 since none of those are lower than 20
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Idrk tbh but I mean did u figure it out ?