I think your answer would Be A. Because historians mostly study written documents, while archaeologists uncover fossils and buildings.
When discussing Newton's laws of motion, particularly Newton's third law of motion, the terms that almost everyone will use are "action" and "reaction".
You must not take this to mean that they understand what they're talking about.
Answer: 20.2 m/s
Explanation:
From the question above, we have the following data;
M1 = 800kg
M2 = 1200kg
V1 = 13m/s
V2 = 25m/s
U (common velocity) =?
M1V1 + M2V2 = (M1 + M2). U
(800*13) + (1200*25) = (800+1200) * U
10400 + 30000 = 2000u
40400 = 2000u
U = 40400 / 2000
U = 20.2 m/s
Answer:
![\omega = 22.67 rad/s](https://tex.z-dn.net/?f=%5Comega%20%3D%2022.67%20rad%2Fs)
Explanation:
Here we can use energy conservation
As per energy conservation conditions we know that work done by external source is converted into kinetic energy of the disc
Now we have
![W = \frac{1}{2}I\omega^2](https://tex.z-dn.net/?f=W%20%3D%20%5Cfrac%7B1%7D%7B2%7DI%5Comega%5E2)
now we know that work done is product of force and displacement
so here we have
![W = F.d](https://tex.z-dn.net/?f=W%20%3D%20F.d)
![W = (44 N)(0.9 m) = 39.6 J](https://tex.z-dn.net/?f=W%20%3D%20%2844%20N%29%280.9%20m%29%20%3D%2039.6%20J)
now for moment of inertia of the disc we will have
![I = \frac{1}{2}mR^2](https://tex.z-dn.net/?f=I%20%3D%20%5Cfrac%7B1%7D%7B2%7DmR%5E2)
![I = \frac{1}{2}(7 kg)(0.21^2)](https://tex.z-dn.net/?f=I%20%3D%20%5Cfrac%7B1%7D%7B2%7D%287%20kg%29%280.21%5E2%29)
![I = 0.154 kg m^2](https://tex.z-dn.net/?f=I%20%3D%200.154%20kg%20m%5E2)
now from above equation we will have
![39.6 = \frac{1}{2}(0.154)\omega^2](https://tex.z-dn.net/?f=39.6%20%3D%20%5Cfrac%7B1%7D%7B2%7D%280.154%29%5Comega%5E2)
![\omega = 22.67 rad/s](https://tex.z-dn.net/?f=%5Comega%20%3D%2022.67%20rad%2Fs)