The spoon to transfer 40 J of energy to your hand is descibed as follows
<u>Explanation:</u>
Given area of cross section of copper spoon is A = 20mm into 1.5 mm
temperature difference is DT = (100 minus 35) = 65 0C
length of the spoon is l = 18 cm,
amount of heat should be transfer Q = 40 J
coefficient of thermal conductivity of copper k = 400 W by mk
we know that the thermal conductivity is Q by t = k into A into DT by l
t = Q into l by k into A into DT
t = (40 into 0.18) by 
t = 9.23 s
When an airplane is flying straight and level at a constant speed, the lift it produces balances its weight, and the thrust it produces balances its drag. However, this balance of forces changes as the airplane rises and descends, as it speeds up and slows down, and as it turns.
Answer:
A) 12.08 m/s
B) 19.39 m/s
Explanation:
A) Down the hill, we will apply Newton’s second law of motion in the downward direction to get:
mg(sinθ) – F_k = ma
Where; F_k is frictional force due to kinetic friction given by the formula;
F_k = (μ_k) × F_n
F_n is normal force given by mgcosθ
Thus;
F_k = μ_k(mg cosθ)
We now have;
mg(sinθ) – μ_k(mg cosθ) = ma
Dividing through by m to get;
g(sinθ) – μ_k(g cosθ) = a
a = 9.8(sin 12.03) - 0.6(9.8 × cos 12.03)
a = -3.71 m/s²
We are told that distance d = 24.0 m and v_o = 18 m/s
Using newton's 3rd equation of motion, we have;
v = √(v_o² + 2ad)
v = √(18² + (2 × -3.71 × 24))
v = 12.08 m/s
B) Now, μ_k = 0.10
Thus;
a = 9.8(sin 12.03) - 0.1(9.8 × cos 12.03)
a = 1.08 m/s²
Using newton's 3rd equation of motion, we have;
v = √(v_o + 2ad)
v = √(18² + (2 × 1.08 × 24))
v = 19.39 m/s
Answer: SG = 2.67
Specific gravity of the sand is 2.67
Explanation:
Specific gravity = density of material/density of water
Given;
Mass of sand m = 100g
Volume of sand = volume of water displaced
Vs = 537.5cm^3 - 500 cm^3
Vs = 37.5cm^3
Density of sand = m/Vs = 100g/37.5 cm^3
Ds = 2.67g/cm^3
Density of water Dw = 1.00 g/cm^3
Therefore, the specific gravity of sand is
SG = Ds/Dw
SG = (2.67g/cm^3)/(1.00g/cm^3)
SG = 2.67
Specific gravity of the sand is 2.67
Answer:
The answer is not correct.
Explanation:
Stu's answer is not correct, the equation to use is known as the law of ohm. In which the voltage is defined as the product of the current by the resistance, then we will see this equation.
![V = I*R\\where:\\I = current [amp]\\R = resistance [ohm]\\V = voltage [volts]\\](https://tex.z-dn.net/?f=V%20%3D%20I%2AR%5C%5Cwhere%3A%5C%5CI%20%3D%20current%20%5Bamp%5D%5C%5CR%20%3D%20resistance%20%5Bohm%5D%5C%5CV%20%3D%20voltage%20%5Bvolts%5D%5C%5C)
In order to find resistance, this term is found multiplying the current on the right side of the equation, therefore the current will be divided on the left side of the equation.
![R=\frac{V}{I} \\replacing:\\R=\frac{4}{0.5} \\R=8[ohms]](https://tex.z-dn.net/?f=R%3D%5Cfrac%7BV%7D%7BI%7D%20%5C%5Creplacing%3A%5C%5CR%3D%5Cfrac%7B4%7D%7B0.5%7D%20%5C%5CR%3D8%5Bohms%5D)
That is the reason that the result found by Stu is not correct.
