I think it would be Newton’s second law
C. Three isotopes of the same element because the number of electrons and protons remain the same but the number of neutrons in the nucleus are different. This means that the isotopes have different masses to each other but the same chemical properties.
Answer:
0.031 W
Explanation:
The power used is equal to the rate of work done:
![P=\frac{W}{t}](https://tex.z-dn.net/?f=P%3D%5Cfrac%7BW%7D%7Bt%7D)
where
P is the power
W is the work done
t is the time taken to do the work W
In this problem, we have:
W = 900 J is the work done by the motor
t = 8 h is the time taken
We have to convert the time into SI units; keeping in mind that
1 hour = 3600 s
We have
![t=8\cdot 3600 =28,800 s](https://tex.z-dn.net/?f=t%3D8%5Ccdot%203600%20%3D28%2C800%20s)
And therefore, the power used is
![W=\frac{900}{28800}=0.031 W](https://tex.z-dn.net/?f=W%3D%5Cfrac%7B900%7D%7B28800%7D%3D0.031%20W)
Solution :
Acceleration due to gravity of the earth, g ![$=\frac{GM}{R^2}$](https://tex.z-dn.net/?f=%24%3D%5Cfrac%7BGM%7D%7BR%5E2%7D%24)
![$g=\frac{G(4/3 \pi R^2 \rho)}{R^2}=G(4/3 \pi R \rho)$](https://tex.z-dn.net/?f=%24g%3D%5Cfrac%7BG%284%2F3%20%5Cpi%20R%5E2%20%5Crho%29%7D%7BR%5E2%7D%3DG%284%2F3%20%5Cpi%20R%20%5Crho%29%24)
Acceleration due to gravity at 1000 km depths is :
![$g=G\left(\frac{4}{3}\pi (R-d) \rho\right)$](https://tex.z-dn.net/?f=%24g%3DG%5Cleft%28%5Cfrac%7B4%7D%7B3%7D%5Cpi%20%28R-d%29%20%5Crho%5Cright%29%24)
![$g=6.67 \times 10^{-11}\left(\frac{4}{3}\times 3.14 \times (6371-1000) \times 5.5 \times 10^3\right)$](https://tex.z-dn.net/?f=%24g%3D6.67%20%5Ctimes%2010%5E%7B-11%7D%5Cleft%28%5Cfrac%7B4%7D%7B3%7D%5Ctimes%203.14%20%5Ctimes%20%286371-1000%29%20%5Ctimes%205.5%20%5Ctimes%2010%5E3%5Cright%29%24)
![$= 822486 \times 10^{-8}$](https://tex.z-dn.net/?f=%24%3D%20822486%20%5Ctimes%2010%5E%7B-8%7D%24)
![$=0.822 \times 10^{-2} \ km/s$](https://tex.z-dn.net/?f=%24%3D0.822%20%5Ctimes%2010%5E%7B-2%7D%20%5C%20km%2Fs%24)
= 8.23 m/s
Acceleration due to gravity at 2000 km depths is :
![$g=G\left(\frac{4}{3}\pi (R-d) \rho\right)$](https://tex.z-dn.net/?f=%24g%3DG%5Cleft%28%5Cfrac%7B4%7D%7B3%7D%5Cpi%20%28R-d%29%20%5Crho%5Cright%29%24)
![$g=6.67 \times 10^{-11}\left(\frac{4}{3}\times 3.14 \times (6371-2000) \times 5.5 \times 10^3\right)$](https://tex.z-dn.net/?f=%24g%3D6.67%20%5Ctimes%2010%5E%7B-11%7D%5Cleft%28%5Cfrac%7B4%7D%7B3%7D%5Ctimes%203.14%20%5Ctimes%20%286371-2000%29%20%5Ctimes%205.5%20%5Ctimes%2010%5E3%5Cright%29%24)
![$= 673552 \times 10^{-8}$](https://tex.z-dn.net/?f=%24%3D%20673552%20%5Ctimes%2010%5E%7B-8%7D%24)
![$=0.673 \times 10^{-2} \ km/s$](https://tex.z-dn.net/?f=%24%3D0.673%20%5Ctimes%2010%5E%7B-2%7D%20%5C%20km%2Fs%24)
= 6.73 m/s
Acceleration due to gravity at 3000 km depths is :
![$g=G\left(\frac{4}{3}\pi (R-d) \rho\right)$](https://tex.z-dn.net/?f=%24g%3DG%5Cleft%28%5Cfrac%7B4%7D%7B3%7D%5Cpi%20%28R-d%29%20%5Crho%5Cright%29%24)
![$g=6.67 \times 10^{-11}\left(\frac{4}{3}\times 3.14 \times (6371-3000) \times 5.5 \times 10^3\right)$](https://tex.z-dn.net/?f=%24g%3D6.67%20%5Ctimes%2010%5E%7B-11%7D%5Cleft%28%5Cfrac%7B4%7D%7B3%7D%5Ctimes%203.14%20%5Ctimes%20%286371-3000%29%20%5Ctimes%205.5%20%5Ctimes%2010%5E3%5Cright%29%24)
![$= 3371 \times 153.86 \times 10^{-8}$](https://tex.z-dn.net/?f=%24%3D%203371%20%5Ctimes%20153.86%20%5Ctimes%2010%5E%7B-8%7D%24)
= 5.18 m/s
Acceleration due to gravity at 4000 km depths is :
![$g=G\left(\frac{4}{3}\pi (R-d) \rho\right)$](https://tex.z-dn.net/?f=%24g%3DG%5Cleft%28%5Cfrac%7B4%7D%7B3%7D%5Cpi%20%28R-d%29%20%5Crho%5Cright%29%24)
![$g=6.67 \times 10^{-11}\left(\frac{4}{3}\times 3.14 \times (6371-4000) \times 5.5 \times 10^3\right)$](https://tex.z-dn.net/?f=%24g%3D6.67%20%5Ctimes%2010%5E%7B-11%7D%5Cleft%28%5Cfrac%7B4%7D%7B3%7D%5Ctimes%203.14%20%5Ctimes%20%286371-4000%29%20%5Ctimes%205.5%20%5Ctimes%2010%5E3%5Cright%29%24)
![$= 153.84 \times 2371 \times 10^{-8}$](https://tex.z-dn.net/?f=%24%3D%20153.84%20%5Ctimes%202371%20%5Ctimes%2010%5E%7B-8%7D%24)
![$=0.364 \times 10^{-2} \ km/s$](https://tex.z-dn.net/?f=%24%3D0.364%20%5Ctimes%2010%5E%7B-2%7D%20%5C%20km%2Fs%24)
= 3.64 m/s
You can try to explain it by using a parallel between their and your societies .