Answer:
The average power the student expended to overcome gravity is 560W, Watts is a units of work it is Joules /time or kg*
/ ![s^{3}](https://tex.z-dn.net/?f=s%5E%7B3%7D)
Explanation:
Weight = 700N
![F= m*g*h \\m*g= 700N\\F= 700N*h\\F=700N*8m\\F= 5600 N*m \\F=5600 J](https://tex.z-dn.net/?f=F%3D%20m%2Ag%2Ah%20%5C%5Cm%2Ag%3D%20700N%5C%5CF%3D%20700N%2Ah%5C%5CF%3D700N%2A8m%5C%5CF%3D%205600%20N%2Am%20%5C%5CF%3D5600%20J)
The power is the work in (Joules) or (N*m) in a determinate time (s) to get Watts (W) units for work
![Work= \frac{5600 J}{10s} = \frac{5600 \frac{kg*m^{2} }{s^{2} } }{10 s} \\Work= 560\frac{kg*m^{2} }{s^{3} } \\Work =560 W](https://tex.z-dn.net/?f=Work%3D%20%5Cfrac%7B5600%20J%7D%7B10s%7D%20%3D%20%5Cfrac%7B5600%20%5Cfrac%7Bkg%2Am%5E%7B2%7D%20%7D%7Bs%5E%7B2%7D%20%7D%20%7D%7B10%20s%7D%20%20%5C%5CWork%3D%20560%5Cfrac%7Bkg%2Am%5E%7B2%7D%20%7D%7Bs%5E%7B3%7D%20%7D%20%5C%5CWork%20%3D560%20W)
Answer:
0.256 hours
Explanation:
<u>Vectors in the plane
</u>
We know Office A is walking at 5 mph directly south. Let
be its distance. In t hours he has walked
![X_A=5t\ \text{miles}](https://tex.z-dn.net/?f=X_A%3D5t%5C%20%5Ctext%7Bmiles%7D)
Office B is walking at 6 mph directly west. In t hours his distance is
![X_B=6t\ \text{miles}](https://tex.z-dn.net/?f=X_B%3D6t%5C%20%5Ctext%7Bmiles%7D)
Since both directions are 90 degrees apart, the distance between them is the hypotenuse of a triangle which sides are the distances of each office
![D=\sqrt{X_A^2+X_B^2}](https://tex.z-dn.net/?f=D%3D%5Csqrt%7BX_A%5E2%2BX_B%5E2%7D)
![D=\sqrt{(5t)^2+(6t)^2}](https://tex.z-dn.net/?f=D%3D%5Csqrt%7B%285t%29%5E2%2B%286t%29%5E2%7D)
![D=\sqrt{61}t](https://tex.z-dn.net/?f=D%3D%5Csqrt%7B61%7Dt)
This distance is known to be 2 miles, so
![\sqrt{61}t=2](https://tex.z-dn.net/?f=%5Csqrt%7B61%7Dt%3D2)
![t =\frac{2}{\sqrt{61}}=0.256\ hours](https://tex.z-dn.net/?f=t%20%3D%5Cfrac%7B2%7D%7B%5Csqrt%7B61%7D%7D%3D0.256%5C%20hours)
t is approximately 15 minutes
long does it take to boil away 2.40 kg of the liquid.
Boiling point of He is ![$T=4.2 \mathrm{k}$](https://tex.z-dn.net/?f=%24T%3D4.2%20%5Cmathrm%7Bk%7D%24)
Latent heat of vapourization ![$L=2.00 \times 10^4 \mathrm{~J} / \mathrm{kg}$](https://tex.z-dn.net/?f=%24L%3D2.00%20%5Ctimes%2010%5E4%20%5Cmathrm%7B~J%7D%20%2F%20%5Cmathrm%7Bkg%7D%24)
Power of electrical heater ![$P=30 \mathrm{w}$](https://tex.z-dn.net/?f=%24P%3D30%20%5Cmathrm%7Bw%7D%24)
mass of liquid is ![$m=2.40 \mathrm{~kg}$](https://tex.z-dn.net/?f=%24m%3D2.40%20%5Cmathrm%7B~kg%7D%24)
amount of heat required to boil
![$$\begin{aligned}&Q=m L \\&Q=2.40 \times 2 \times 10^4 \mathrm{~J} \\&Q=4.80 \times 10^4 \mathrm{~J}\end{aligned}$$](https://tex.z-dn.net/?f=%24%24%5Cbegin%7Baligned%7D%26Q%3Dm%20L%20%5C%5C%26Q%3D2.40%20%5Ctimes%202%20%5Ctimes%2010%5E4%20%5Cmathrm%7B~J%7D%20%5C%5C%26Q%3D4.80%20%5Ctimes%2010%5E4%20%5Cmathrm%7B~J%7D%5Cend%7Baligned%7D%24%24)
Power ![$p=\frac{\text { work }}{\text { time }}=\frac{\text { Energy }}{\text { Time }}$](https://tex.z-dn.net/?f=%24p%3D%5Cfrac%7B%5Ctext%20%7B%20work%20%7D%7D%7B%5Ctext%20%7B%20time%20%7D%7D%3D%5Cfrac%7B%5Ctext%20%7B%20Energy%20%7D%7D%7B%5Ctext%20%7B%20Time%20%7D%7D%24)
![$$\begin{aligned}P &=\frac{Q}{t} \\\text { tine } t &=\frac{Q}{P}=\frac{4.80 \times 10^4 \mathrm{~J}}{10} \\t &=4.80 \times 10^3 \text { seconds }\end{aligned}$$](https://tex.z-dn.net/?f=%24%24%5Cbegin%7Baligned%7DP%20%26%3D%5Cfrac%7BQ%7D%7Bt%7D%20%5C%5C%5Ctext%20%7B%20tine%20%7D%20t%20%26%3D%5Cfrac%7BQ%7D%7BP%7D%3D%5Cfrac%7B4.80%20%5Ctimes%2010%5E4%20%5Cmathrm%7B~J%7D%7D%7B10%7D%20%5C%5Ct%20%26%3D4.80%20%5Ctimes%2010%5E3%20%5Ctext%20%7B%20seconds%20%7D%5Cend%7Baligned%7D%24%24)
The heat or energy that is absorbed or released during a substance's phase shift is known as latent heat. It could go from a solid to a liquid or from a liquid to a gas, or vice versa. Enthalpy, a characteristic of heat, is connected to latent heat.
The heat that is used or lost as matter melts and transitions from a solid to a fluid form at a constant temperature is known as the latent heat of fusion.
Due to the fact that during softening the heat energy anticipated to transform the substance from solid to fluid at air pressure is the latent heat of fusion and that the temperature remains constant during the process, the "enthalpy" of fusion is a latent heat. The enthalpy change of any quantity of material during dissolution is known as the latent heat of fusion.
For learn more about Latent heat of vaporization, visit: brainly.com/question/14980744
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Answer:
![a = 0.53 m/s^2](https://tex.z-dn.net/?f=a%20%3D%200.53%20m%2Fs%5E2)
Explanation:
initially the merry go round is at rest
after 6.73 s the merry go round will accelerates to 20 rpm
so final angular speed is given as
![\omega = 2\pi f](https://tex.z-dn.net/?f=%5Comega%20%3D%202%5Cpi%20f)
![\omega = 2\pi ( \frac{20}{60})](https://tex.z-dn.net/?f=%5Comega%20%3D%202%5Cpi%20%28%20%5Cfrac%7B20%7D%7B60%7D%29)
![\omega = 2.10 rad/s](https://tex.z-dn.net/?f=%5Comega%20%3D%202.10%20rad%2Fs)
so final tangential speed is given as
![v = r\omega](https://tex.z-dn.net/?f=v%20%3D%20r%5Comega)
![v = 1.71 (2.10) = 3.58 m/s](https://tex.z-dn.net/?f=v%20%3D%201.71%20%282.10%29%20%3D%203.58%20m%2Fs)
now average acceleration of the girl is given as
![a = \frac{v_f - v_i}{\Delta t}](https://tex.z-dn.net/?f=a%20%3D%20%5Cfrac%7Bv_f%20-%20v_i%7D%7B%5CDelta%20t%7D)
![a = \frac{3.58 - 0}{6.73}](https://tex.z-dn.net/?f=a%20%3D%20%5Cfrac%7B3.58%20-%200%7D%7B6.73%7D)
![a = 0.53 m/s^2](https://tex.z-dn.net/?f=a%20%3D%200.53%20m%2Fs%5E2)