Answer:
0.169
Explanation:
There are three forces acting on the crate along the horizontal direction:
- The pushing force of the first worker, F1 = 450 N forward
- The pushing force of the second worker, F2 = 330 N forward
- The frictional force
acting backward
The crate slides with constant speed, so its acceleration is zero: a = 0. This means that we can write Newton's second law as
![\sum F = ma = 0\\F_1 + F_2 - F_f = 0](https://tex.z-dn.net/?f=%5Csum%20F%20%3D%20ma%20%3D%200%5C%5CF_1%20%2B%20F_2%20-%20F_f%20%3D%200)
The frictional force can be rewritten as
![F_f = \mu mg](https://tex.z-dn.net/?f=F_f%20%3D%20%5Cmu%20mg)
where
is the coefficient of kinetic friction
m = 470 kg is the mass of the crate
g = 9.8 m/s^2 is the acceleration due to gravity
Substituting everything into the previous equation, we find:
![F_1 + F_2 - \mu mg = 0\\\mu = \frac{F_1 + F_2}{mg}=\frac{450 N+330 N}{(470 kg)(9.8 m/s^2)}=0.169](https://tex.z-dn.net/?f=F_1%20%2B%20F_2%20-%20%5Cmu%20mg%20%3D%200%5C%5C%5Cmu%20%3D%20%5Cfrac%7BF_1%20%2B%20F_2%7D%7Bmg%7D%3D%5Cfrac%7B450%20N%2B330%20N%7D%7B%28470%20kg%29%289.8%20m%2Fs%5E2%29%7D%3D0.169)
Answer:
Not necessarily
Explanation:
Rain needs some mechanism such as instability of vertical air movement.
I'm not 100% sure, but I believe what you mean is when they eject the old propulsion motors. Yes, they land in the ocean and the US Navy retrieves them for later use.