Answer:
10 seconds
Explanation:
x = x₀ + v₀ t + ½ at²
250 = 0 + (0) t + ½ (5) t²
250 = 2.5 t²
t² = 100
t = 10
It takes 10 seconds to land from a height of 250 ft.
Answer:
No, distance is more important.
Answer:
sound is how an animal or human perceives a sound wave
Answer:
![W=4037.36\ J](https://tex.z-dn.net/?f=W%3D4037.36%5C%20J)
Explanation:
Given:
mass of ice melted, ![m=3.3\times10^{-2}\ kg](https://tex.z-dn.net/?f=m%3D3.3%5Ctimes10%5E%7B-2%7D%5C%20kg)
time taken by the ice to melt, ![t=5\ min=300\ s](https://tex.z-dn.net/?f=t%3D5%5C%20min%3D300%5C%20s)
latent heat of the ice, ![L=3.34\times 10^5\ J](https://tex.z-dn.net/?f=L%3D3.34%5Ctimes%2010%5E5%5C%20J)
Now the heat rejected by the Carnot engine:
![Q_R=m.L](https://tex.z-dn.net/?f=Q_R%3Dm.L)
![Q_R=0.033\times 3.34\times 10^5](https://tex.z-dn.net/?f=Q_R%3D0.033%5Ctimes%203.34%5Ctimes%2010%5E5)
![Q_R=11022\ J](https://tex.z-dn.net/?f=Q_R%3D11022%5C%20J)
Since we have boiling water as hot reservoir so:
![T_H=373\ K](https://tex.z-dn.net/?f=T_H%3D373%5C%20K)
The cold reservoir is ice, so:
![T_L=273\ K](https://tex.z-dn.net/?f=T_L%3D273%5C%20K)
Now the efficiency:
![\eta=1-\frac{T_L}{T_H}](https://tex.z-dn.net/?f=%5Ceta%3D1-%5Cfrac%7BT_L%7D%7BT_H%7D)
![\eta=1-\frac{273}{373}](https://tex.z-dn.net/?f=%5Ceta%3D1-%5Cfrac%7B273%7D%7B373%7D)
![\eta=26.81\%](https://tex.z-dn.net/?f=%5Ceta%3D26.81%5C%25)
Now form the law of energy conservation:
Heat supplied:
![Q_S-W=Q_R](https://tex.z-dn.net/?f=Q_S-W%3DQ_R)
where:
heat supplied to the engine
![Q_S-\eta\times Q_S=Q_R](https://tex.z-dn.net/?f=Q_S-%5Ceta%5Ctimes%20Q_S%3DQ_R)
![Q_S(1-\eta)=Q_R](https://tex.z-dn.net/?f=Q_S%281-%5Ceta%29%3DQ_R)
![Q_S=\frac{11022}{1-0.2681}](https://tex.z-dn.net/?f=Q_S%3D%5Cfrac%7B11022%7D%7B1-0.2681%7D)
![Q_S=15059.36\ J](https://tex.z-dn.net/?f=Q_S%3D15059.36%5C%20J)
Now the work done:
![W=Q_S-Q_R](https://tex.z-dn.net/?f=W%3DQ_S-Q_R)
![W=15059.36-11022](https://tex.z-dn.net/?f=W%3D15059.36-11022)
![W=4037.36\ J](https://tex.z-dn.net/?f=W%3D4037.36%5C%20J)